I'm kind of interested in experimenting with just intonation and microtones in modplug. Would there be any way for me to tune different notes individually without having a new instrument for each note? If not, I can post a feature request based on this post.
If there are any synths that can tune notes individually with more flexibility than Oatmeal, I'd love to hear about those too.
Yes, you can do microtuning in the MPTM format: http://wiki.openmpt.org/Manual:_Tunings
ZynAddSubFx is another VSTi that can do microtuning, although its GUI might take a while to get used to.