I would like to see Behringer create a clone of the Oberheim Xpander.
A couple reasons why they should:

The Xpander is entirely built around CEM chips. Although Behringer haven't cloned the CEM3374 (Dual Oscillator) or CEM3372 (24db multimode Filter/Mix/VCA).
They have cloned essentially the simpler versions of both. They just need to double up the V3340 oscillator per voice.
The V3320 can be used for all the filter types of the Xpander. Lowpass, Highpass, Notch, Bandpass.

I don't think they need to clone the other chips they just need to use what they've already got the right way.

But I propose that they don't just clone it outright. Here's where I think it could be really useful:
Tom Oberheim envisioned the Xpander as a complex modular synth in a box.

The beauty of the original Xpander was that each of the 6 internal voices could be fed each their own CV/Gate signals which let the Xpander act as 6 separate analog mono synths each running a separate patch.

Each of these was limited to a single CV/Gate pair though, which really limits the power of the Xpander.

Well what if this "Behringer Xpander" had a full mini CV patch panel for each voice complete with ins and outs? So you could inter-patch voices or just sequence a bunch of parameters of each of them independently.

If it was made in a more "upright" fashion it could almost be like a full 6-voice eurorack system with patch memory. Imagine that, all the power of a complex modular system (x6) and you can save the whole setup (minus the physical patch). Pair it with a sequencer and you've got amazing live set ability right there. Ship it with a lid and a handle just like a Eurorack case.

Take the whole Xpander panel and move the screens and knobs closer together and put a big 6-part patch panel on the side. With buttons to select each part.

One of the reasons I think this can work so well is the multimode filter in the Xpander makes it easy to put together ensembles of patches that work well together. It makes it a little less redundant to have so many copies of the same voice architecture.

Anyway, just a thought really. I think it's a great way for them to revisit an old classic and give it a new spin so it's not just a 1:1 clone. It also uses the CoolAudio chips they already have so there's not a huge leap there.

Have a look at the JD-XA. Its ticking most of the boxes of your concept.

Multitimbral, can stack and poly voices freely, has a sequencer, has patch memory, all knob based parameters are modulatable via CC, has filter sounding oberheim-y, has other filters, has 3 Env and 3 Lfo per voice .. you get the idea...

I'm more interested in something I can control with CV

Fwiw, Behringer is already making or slated to make a bunch of synths based on CEM chip designs

If you want an expander like that with individual voices controllable via CV and based on CEM you could just as easily get 6 of the new Crave's or 6 Neutron's, or 6 Pro One's or a mix and match of any of the above

6 of those units in any combination would be less than 2 grand

Do you want to use your already bought eurorack modulators? Because if its just for modulation in general, CC works just as well.

I use Vermona qMI2 and Doepfer A92 CVM16 to be able to do it any way i need.

In general i dont have positive experiences with CV on polyphonic stuff. And when it comes to having 6 mono voices (as your concept suggests) i prefer 6 different ones (typical eurorack) or dual for stereo use (like Oberheim 2-voice).

+1 to the idea of an Xpander / Matrix-12 clone; it'd be the likely progression beyond the UB-Xa.

That said–I'd rather see the DeepMind approach taken: start with a homage, end up with a completely different product that suggests the original but is far better in terms of facilities. The user interface concept of the Xpander has already been improved upon to a large degree by Sequential/DSI (e.g., Prophet-12 desktop).

The CEM 3372 itself is an interesting beast, and is (to a large degree) part of the Xpander sound (as well as that of the Prophet-600 and Chroma Polaris), so there would need to be some tuning of the outer circuits to mimic the VCA's soft clipping.

I can't speak to CV/gate functionality on such a clone, but I would imagine that to add a significant amount of cost to the unit; let's start with working voice / filters and multi-timbrality first (need not be just six, maybe eight?).

This exists--it's called the Solaris.

Agreed that it would be amazing to clone the Xpander. I have one, and it's an amazing synth that does stuff that few others can. What it doesn't do well, however, is 'bread and butter' synth sounds. Something like a Prophet 600 gligli is much better for that, and the reason is in the chips.

Xpander used later stage Curtis chips that didn't sound as good, the oscillators in the 3374 have this annoying mid-rangey sonic coating that is difficult to eq away (which gets in the way of the basic tone of the chroma polaris or the akai vco synths). With a lot of resonance you don't hear it as much (ie: Polaris), and with the non-standard filter types of the Xpander, it ceases to matter. But taken on its own, the 3374 ain't a great oscillator tone. The 3340, the reissues vco chip, is beyond classic (Prophet 600, Obxa, etc.). If you're gonna do an Xpander reissue that in any way 'improves' upon the original, use that chip instead! Xpander has many strong points, but its raw oscillator tone is simply not one of them, 3340 all the way.

Also worth saying that the 'filter trick' that Tom Oberheim used to get a standard Curtis chip to give him 15 filter types is mostly done with the wiring AROUND the chip. Any old Curtis chip filter will do if the wiring around it is right. Each Curtis has its own sound, but the 3372 is the same curtis filter used in the Prophet 600 (I think, online account seem to vary!), and that's def one of the better ones. Point is, in terms of chips, he's already there.

As for interface, the interface on Xpander is amazing for what it could with the technology, but it's still not what I'd call immediate. So many easy ways that a modern DSP could improve upon that aspect without hurting the sonics at all.

The modular side of it is a major attraction to some, but semi useless to others. I'm more a traditional player kinda guy, so I've never used the CV options, but I can see where the modular folks would love it, and agreed, there's no reason why couldn't have a patchbay that goes way beyond CV. The ideal thing to do would be reissue the Xpander without CV, but then have a breakout unit (Xpander Expander?!) that has tons of CV for the modular crowd. Midi CC is great, but not if you're into modular.

The issue is only one of those is using the 3320 and not in a multimode configuration. It's not enough to just use the same chip, it depends on HOW it's used. The 3320 is ready to be wired up to be all the filter types I mentioned but not every synth uses it that way.

B should be a gentleman and ASK The Mighty Tom Oberheim for PERMISSION, even if he doesn't need it legally. If Tom is keen, B should HIRE him to assist in the Xpander II. This would be such a great thing in so many ways in contrast with the out and out theft / copying that got them where they are, and the shameful episode of suing their critics.

In other suggestions: Leopards should change their spots.

Well I don't really think it HAS to be an Xpander clone. As FromThePuggle said the Xpander is an inherently flawed synthesizer in both interface and sonics. A new synth "inspired" by the Xpander would be a lot better, using the chips they've already got.