There were brackets made that hang from under the front of the trailer, behind the tounge. Hard to describe, and I don't have a picture, but there is one on my trailer. It is a simple framework that is hinged on the back edge to the belly of the trailer, and latched in the front, and secured w/ a pin. this front "handle" is easily reachable from the front curbside corner of the trailer, right next to where the a-frame disappears into the skin. just remove the pin, and un-latch the gizmo, and the front drops down to the ground, allowing you to slide your spare onto the "rack". lift it up, re-latch and pin, and your spare is securely suspended under the trailer.
I don't know if you can still get one of these things anywhere....didn't see them listed on Andy's site, but perhaps he knows if they're obtainable. maybe from an RV salvage place that I see mentioned here (?)