AVR-Chat

I've been asked to make a device which will produce sounds, notes and
music. This is an add on to a unit controlled by a mega128.
We've previously made something for this customer which plays back WAV
samples off a compact flash card, but this time they would like
something more synthesised. We have also made a simple synth using a
mega8 generating a wave using PWM from a wavetable, but it's very basic
and sounds it.

Mobile phones do this sort of thing routinely these days, but you can't
get the "synth" chips you used to be able to buy like the good old
AY-3-8910 and that type of thing.

Has anyone done anything like this with up to date technology?

-- 
Tim Mitchell