Well, I've had a fiddle around with it, and now I think, "Yes, definately!" It could very well work, my only question is how much space is it possible to have in a map? What I'm getting at is that some RPGs would have to have a fair bit of room to have stuff in, so you don't want a map the default size. However, I didn't try enlarging it, so I don't know what the limit is.
Anyway, I probably won't be able to help with the sprite editing and all that (though it looks like Super Munch might be able to help you with that bit), but I could work with any scripts if needed (I can usually learn new scripting methods fairly quickly as I've used very many of them in the past), and I could also do music seeing as I have MIDI software and can compose music (says me, anyway
).