Mike Nelson is quite correct that the voice architecture of the VFX family is unique. The reason, incidentally, is that the VFX series reserve 2 of the six slots used for timbres for an optional tuning table. Thus, the tuning of the synth is also stored with the information about the timbre. This makes it very difficult even to conceptually transfer from the VFX to some other synth, since you can't be sure whether some of the data in the patch setup is a tuning table or infromation to set the timbre.
Rubber Chicken sells software that is supposed to take VFX sequences and turn them into standard midi files. You can find more info at www.chickensys.com
Rubber Chicken is also an excellent source for Ensoniq patches, editors, etc. (I don't work for 'em and have no financial interest in 'em, but have looked over their website. It's got an awesome set of Ensoniq editor software and EPS/ASR-X samples.)
On a much sadder note, the rumors have been circulating that Ensoniq itself is pretty much going out of the music-instrument manufacturing biz. We all suspected as much when they fired their entire R&D staff 3 years ago, and it looks as though this is the last gasp.
Does anyone know if this is true or not? If so, it's a sad day. Ensoniq produced some of the best synths around for nigh on 15 years.