Sounds awesome,
There are many great sounding " little synths " from 3rd party guys and Creamware.
The big synths take too much time for their presets live, such as QWave, and Solaris. They can be made to do mini presets, which would load faster, but defeats the purpose. I love ProWave for live work. For my particular needs it is the ultimate Live Soft synth you can have.
Such a device would be spectacular, I think it's a great idea, and this is what makes this forum so valuable IMO. Several heads, are better than one, or the few. ( Sounds Like Spock

)
The " little synths " that I spoke of like Saturn ( my favorite ), and others, Poison, Prism, Inferno, etc., all have a different flavor, but sound really good blended. I did this at first w/ Saturn, the FATTEST little free BASTARD I ever heard. Saturn also allows polyphony settings per preset. ProWave also does this, as I have some patches that are really DSP hungry, I set the poly to 12 in the live bar, and have certain presets which would downsize to 8 when loaded, very nice.
The multi FX device works great. I have loaded it in an Aux before with SSB Modulator, Celmo Phaza, Hexa Chorus, and PsyQ for a really great shimmering phase shifter that gets applied by twisting one knob on my KS88's. I could see playing ProWave, and morphing in some multi synth textures, or just calling up a preset with 4 synths, all with different attacks, and octaves for a really FAT WIDE PAD. This would be a great device for CC5, CC8, MultiControl, and Cyprox also. When controlling 4 synths with a single CC, you can get some really unique sounds.
Scope never ceases to amaze me. The same goes for the ideas of many of my Brotha's here as well.
Great Idea,.....Fuckin' A !!