Hmmm...yea, I'm familiar with what you mean...now, Zakk Wylde, though not very much of a fan of him, I believe he runs two marshall jcm800's (50 watters) into one cab...this is where I kind of got the impression that it was possiable I guess. Now whether or not he switches between the heads i don't know, I figure he probably doesn't. Umm, oh well, if anyone has any ideas that'd be cool...I think it can be done through midi routing setups, but i rather just go buy another Marshall 4x12 if we're talking a solid chunk of money to make the switchable two-heads-into-one-cab setup possiable...Thanks -Matt