The irony is, Yamaha was theoretically right. With
enough oscillators
cross-modulating eachother, you could make filters optional. Where they
got ahead of themselves was thinking they could do that with only six
per voice. Dozens or hundreds, yeah maybe. Six, no.
The DX7 can do many very complex timbres with only six, but who wouldn't like it to
have hundreds.
I used to have an Elektron SidStation in my studio
(sold it), but it was
a device like you're talking about -- a little Midi-controlled silver
box with a real SID chip in it.
I really wished those were available anywhere in Argentina, but haven't seen any yet.
Cheers!