I highly recommend that you check out recumbent trikes. Sure, you can try to build up your buttock muscles and you may have success. Realistically, though it's going to be a long slow process, even if you get supplemental steroids to help. But I think you'll find that pedaling a trike is remarkably similar to pedaling a DF bike, except that you won't be standing on the pedals. Choose carefully and you can be enjoying yourself in a very comfortable seat a week from now.

And no, I never considered a trike until I had to, but it was the best money I've ever spent for pedaling purposes.