"Homemade" Tire Carrier

I have a custom rear bumper that someone made, and was just wondering about putting my spare tire on it. If I took a tire tack (like the side mounting one on XJs) and mounted to to the top of the rear bumper (pointing up) so that it could swing down to release my hatch, would it work?

I haven't really looked much at the latching mechanisms that hold these on, but it seems like it wouldn't be much different than mounting it so that it swings sideways. What does everyone think?

The latching mechanisim and a rubber bumper for vibrations will be the key points.

unless you have a strong roof rack to tie it to you will never get it to stop bouncing.

Fill it w/helium.

Personally, I'd like to see something like this for occasional stowage outside of the cargo compartment - only hinged so that the rear hatch could be opened without having to remove the entire carrier.