This question gets asked a lot on here, I think max jacks are a good alternative to use a creeper, BUT I think in some cases a creeper and ramps or jack stands may be easier, I can't imagine doing much more than brakes and outer axle work at that height. do you work sitting down?
ANYWAY, what does your roof look like, a was recently at a gentlemans house buying some mopar parts and he had a lift in a normal 2 car garage, the roof was pitched from the center out inline with the single large door, he said it was a sheetrocked ceiling he tore down, and exposed the joists, there was a storage space up there that could could about walk around in, he cut the joists one at a time, revamped them (using a lot of the old pieces), crossmember'ed the tops, tied the roof joists together where ever he could, framed it all in and put the lift right under that peak...
he said he can still park 2 cars, he just has to lift one first, lol.. He said it was never a parking garage, always used it for working, so he has boxes, compressors, etc in there and the lift, its a nice space...
What are you trying to do on the lift, I guess would be my question, if its just tires, oil changes, etc, a mid lift is perfect, ig you want to do exhausts, trannies, rear ends, motor swaps, resotrations, etc.. Figure out how to raise the roof and go full sized...