Giant rear projection is a great way to go. You don't need complete light control in your room, but you can still go really big.

There are a few issues though. Their big TV's don't have very good off angle viewing and seem to have a pretty narrow sweet spot, Black levels haven't been very good, and the screen uniformity isn't very good. But, overall, a 90" TV would be a great alternative to a front projector for a lot of folks.