[em2nought]

I've used the top section of a metal bunkbed previously to create a storage space near the ceiling in my garage. You can find those either free or practically free and make a storage area over top of the garage door for cheap compared to those that are specifically made for that sort of thing. Old metal bedframes are a great source of angle iron much cheaper than trying to buy it at the hardware store. People throw them away quite often too.

It looks like you could only get very skinny items above your garage door, but it still might be worthwhile.