Yeah, but do people actually get ideas randomly by wipping out a hummed melodic solo over a progression? Seems to me that soloing is all about repetition and muscle formation and patterns and such. In any genre. The only solo I can think of that may have been brought about by humming is Sweet Child o Mine after the verse and before the chorus, but even still, that's no doubt a product of years and years of playing the same **** over and over. I think if you've got an idea in your head you've no doubt practiced it before or at least played it.