Sorry for the late reply, I didn't realize you'd replied.
yes I mean polyphonic by 'poly'.
A ds version of something like operator would be heaven (operator is an FM synth as is megarive chip by the way), especially if this instrument could be implemented in the same ultra flexible way that trackers are able to use there channels in the most flexible way possible (ie multitimbrally). There is actually a megadrive sound chip compatible tracker that someone wrote, I suppose it would be helpful. its called 'TFM Music Maker'. I think this is the authors website
http://shiru.untergrund.net/software.htmPerhaps you code also take a sneaky peak at the code that creates the sound in the megadrive emulator, or does it have to be open source to do that? Here's a link
http://www.neoflash.com/forum/index.php/topic,4571.0.htmlI'm not sure what you mean by resources for FM synth but I hope this helps.
If you are worried about the difficulty in people being able to create their own synth sounds with little or no synth programming experience then perhaps it would be best to include a large user created patch (synth sound) library. You could even give the user access to a patch library online via the ds wifi. seeing as any synth sound can be stored in a bunch of parameters which could be contained in just a few bytes then it should be possible. I wouldn't mind contributing!
As per usual I seem to be getting way too excited, but these ideas are worth noting I suppose.
By the way, the wife is getting my DS-10 for xmas so that'll be nice
Cheers.