But isn't it going to get sorta old if every one of your terminators just happens to be standing on their very own personal hill? As if the old termies won't stand out compared to the new ones as it is...
A decent idea though I'll grant you, but I still think rebasing is what's going to be needed. That, or a way to do an extenda-base or something. Maybe make a mold, put the model in it, fill with putty, let dry, pull out of mold, and whoola, bigger base....