Yes, and it can be used to make different variants as well... There was one with the wheels in the concept art of original SW, right? And a hover version would be nice as well... Should I start buying Imperial Assault minis?!?
There was a TRACKED tank idea in the original concept art, yes.
(and an aquatic one that got used in one of the old rpg scenarios).
I don't recall a wheeled one, but I think it was mostly Joe Johnston's stuff in that empire sketchbook that I have.