Also working on a vacuum hose reel solution for my garage ceiling, and had already found Bellevue's video (fun and impressive). My wood skills are intermediate at best, so instead I'm going to try to adapt a wooden cable spool. (Home Depot sells them for $25 (!?), but they gave me one for free since it was a throw-away from their electrical cable area.)
Incidentally, the house we bought 4 years ago came with a central vacuum (works ok). The previous owner kept a 30' hose coiled on a hook in the garage, and also left behind two spare wall-mountable garden hose reels (molded from ABS). It didn't occur to me until I started this project that he might have been trying to adapt them for just this purpose. I took a look at them, and decided the ABS just isn't sturdy enough, nor easy enough to modify, for the larger hose.
Another thought that occurred to me is to put the reel in the attic above the garage, and simply create a collared hole in the ceiling for the hose to drop through--provided I can work out a reliable retraction solution. This would help address any pulling of the hose perpendicular to the direction of the reel, plus eliminate the need to make room for a 2' reel hanging from the ceiling. (Hanging the reel on a swivel mount would help with this, too, but then the stationary connection becomes even more of a challenge.)
I think I can create a swiveling pipe joint with non-matching PVC fittings, but I'll head over to the local vacuum repair store to see if they have any rotating joints. It also looks like many central vacuum hoses these days have a built-in swivel joint where they connect to the wall, so I may not have to cobble anything together if I can use that.
Will post again with success/failure tips.