looking at the site, i like the design for the small keyboard the best. if it has more notes than there is room, a scrollbar can be used.
you have forgotten one very very very important thing in your design though. can you guess what it is?
presets man, presets! so you make a totally rad tuning and you cannot save it anywhere? or you make a 2nd instrument and you want that same awesomeness of tuning contained in that as well? presets! saveable, loadable, adjustable presets!