I was acutally thinking about this the other day. I mean, with software like Peavey Revalver, where you can tweak in tube types and their characterstics in the preamp and power stage, why can't developers enable the end user to "tweak" the amp models on modeling amps? Maybe the Axe already does this, I don't know. But, I'm thinking the guitarist could start out with say a Marshall. Then, through some GUI, he could modify the amps character infinitely (somehow). Much in the same way amp designers swap out capacitor values to modify the voicing, gain, etc., the amp would allow you to change the minute details about the amp. The revalver is the closest I've seen to this, but it would be interesting to make it a stand alone unit...