I don't take pictures... But my dad caught me in the early planning stage of the roof rack/crane scenerio.
Basically I ended up scrapping an old engine hoist. Ditched the hydraulic cylinder and replaced with a solid strut. Strut length makes the top bar hortizontal.
Picture is not exactly the pieces/parts I ended up using in the crane, but you get the idea. Key also was round heavy wall pipe upright and slightly larger round sockets welded into the railing of the rack. This allows the crane to swing and it can be moved to several areas on the rack. I ended up with 4 sockets (4 potential crane locations) on the rack. Rack is bolted clear through the roof ribs and has plywood decking. Crane in picture is in one of the sockets, and other sockets can be seen on the back of the rack... and lying around on the shop floor.
Outside of tire lifting.. also can hang one of those hammock chairs from the crane when chilling in camp.
All assembled with bolts so that it can be broken down and stored in three parts. Vertical piece, hortizontal piece, strut piece. Electric winch was then mounted on the top hortizontal part. All parts can be stashed in a storage box that also has my stovepipe stored in there. Box works as a good bench for beer drinkin on the roof...