I was in a Lowe's looking at plastic covered screw hooks for hanging garden tools on a garage wall and they now have a fold down bicycle storage "hook." It is shaped like a triangle and cradles the top tube of the frame at two points about 14 inches apart. It does not cost much more than $10, if that. You could mount it to the wall. I have played with the idea of mounting it to a piece of 2 x 4 or 2 x 6 about six feet long. Then I would make a base for the 2 x 4 or 2 x 6, possibly one that folds up. I do not have that part worked out yet. Lately Wal-Mart has had a similar bicycle hanger that folds up in two parts. I think I like the Lowe's version better.