We just recently started shipping the SF-24V. You can see it here -
Royer Labs. The electronics are very close to those in the R-122V - a few small changes to accommodate the SF's different ribbon transducers. SF-series ribbons are shorter, narrower, and thinner than those in our R-series mics. The mic's response is dead flat (+/- 1 dB) and it starts its roll-off a few kHz past where R-series mics roll off. It's a more "classic" sounding design, a little less forward in the mids then an R-series mic. It's not as tough as an R-series ribbon, so it likes careful handling and no loud guitars...
Here's a shot of the first prototype SF-24V. David Royer's gold SF-24 had been hanging by a beam in the shop for months and I asked him one day if he was recording us. Turns out he had stuffed tubes in the mic...! I put on some cans and had my brain rearranged. I've heard every Dave design since 1996 - this was the most eye opening.
We'll have a new site up in a few days with more SF-24V info, more pics of the original, more info on the mic. I'll try to post sound samples soon.