Are you satisfied with the sound you can get now with Digital?
If so, just stay digital & maybe spend that 1K on some outboard, quality plugins or save up a little more loot.
If you look hard enough, you can probably find a small sidecar type analog mixer that will sound decent in about that range.
I personally prefer analog hands down, but along with that nice sound come the headaches of board maintenance & the plethora of cabling/patching I gotta do.
Worth it to me for sure, but may not be to all.
The other option you have is a summing mixer.
Probably run a little more than 1K for a real good one, but that may suit you as well & allow you to still use a digital board/controller to control your DAW.
Budget & personal taste will be a major factor.
And keep in mind not all analog is created equal.
Just cuz it's analog doesn't mean it will sound better than your ITB setup.
Not dissin', but I wouldn't call using a Mackie with your Digi an analog setup.
Nothing wrong with the Mackie if it works for you (Hell i started out with an Alesis mixer!!!), but a real analog board would be something of a slightly higher caliber, even it's older, clunkier & dustier.
Personally I'd rather use an old Tascam board than the Mackie.
Those can be had for pennies on dollar these days.
I've used both types, all ITB & then to OTB, now I am back to a full console & even tossed out my DAW Controller.
Theres just no comparison to me, true analog rules.
But you *can* without a doubt achieve mixes/sound of equal caliber with a digital setup if you learn to use it real well & have the right tools.