I have two ideas that are still in my head or on paper. One is an A frame setup like an engine hoist or swingset, but tall enough for the Jeep to drive under and the top to lift off.
The second idea is a metal arm on a swivel, mounted to the corner of my deck. (the deck comes off the second story of our house. The arm swings out from the deck into the backyard, drive the Jeep under it, lift off the top, drive away.