I've often considered shifting to the Prophet 12 and buying perhaps three units, but I'm obviously not too certain about the results.
How about combining a single Prophet-12 module with your Prophet '08 setup? The Prophet-12 can by itself do filters in stereo via DC source while the Prophet '08 gives the solid analog foundation. Could work out very well for your type of music. Plus it will give you a combination of analog and digital waveforms. In this way you don't have to sell everything and try to build a new setup. Instead you can make incremental changes to your setup. Also it seems like the Prophet-12 module have a lower price now than when it was announced.
True, but I don't like the mismatched numbers of voices. The P12's additional four voices would go to waste, so it wouldn't be worth the expense. But one combination that I think would work well would be a Prophet 6 and a Prophet 12 Module in stacked mode. I'd say that would be a very impressive instrument. I wonder if anyone has tried it.
What you've suggested works fine in combining an eight-voice Poly Evolver and a Prophet '08 Module or two. It's basically the same end result as using a P12 Module, but without the wasted voices. I've used that arrangement quite a bit, but I actually found that I liked the instruments better when separate - pure Evolver and pure Prophet '08.
One thing I especially like in keeping the P'08s together is maximizing the PWM. It's quite a sound when the PWM is set to its deepest amounts and fastest rates, according to the register. As we all know, PWM changes according to pitch. One setting that sounds lush in the mid keyboard range sounds overly detuned in the lowest octaves and too mild in the upper. When you've got multiple oscillators and multiple octaves set together, you can adjust each to get the maximum PWM according to pitch range. Now that is a magnificent sound.
Obviously, the Evolver's digital oscillators can't offer PWM, so it's not the PWM monster that the P'08 is. But on another note, the Poly Evolvers have the looks.
Doesn't this picture just warm the cockles of your synthesist's heart?