Well, here's another cat sitting next to an Octave CAT – wonder why that comes up so much.
Actually I am quite interested in the Octave CAT and Kitten synths, I'm trying (yet again) to bid on one on eBay.
In the meantime, I have been trying several methods to emulate them, including building an Emulator X patch. The Kitten is definitely more feasible because it only has one oscillator and thus no FM – FM is nearly impossible to do on the Emulator platform. However, I did one out of MIDI controllers. So the end result is a “Kitten lite” that contains all the oscillator waveforms (Saw, Triangle and Square/PWM), the two independent sub-octave waveforms, square and sine LFOs, filter with realtime cutoff and Q and envelope mod, and of course ADSR envelope.
While not a real Octave Kitten, it's a nice little playable instrument.