I have a Roland Ready Strat and a GR 33-you can set up a patch that you can make each string what ever note you want. true it has some short commings- find a store that has one and give it a try.
here is what i like about the gr 20 33 or the vg99 type guitar sysnthesizers, is the fact that i cant play sax or harmonica or flut or the sitar or the xylaphone but i can play the guitar infact ive got 30 years invested in playing the guitarand at what ever skill levle i have achieved at guitar i could never come close to the same skill level on say a sax or violin or a miramba or what evre type of instrument sound you have on a midi keyboard,(if the on board presets werent enough ) the point is after a short learning curve with the gr 33 i was playing sax parts right from my guitar that would have taken me years (not too mention big bucks) too learn on a real sax. if you got any knowledge at all of what the instrument your trying to play is capleble of and what its not ie. note bending on a guitar is posible but not on a traditional piano, sure some of the nuancess are some what trickey or imposible at this time to recreate, but with some time on the device you can be pretty damn realistic.