I've been meaning to make one of these for a long time Hilton Handcraft - The Log Lift
and finally got around to it last week. Haven't had a chance to use it yet (to load anything into my truck), but I did try lifting a large birch log in my woodpile, and it did the job without causing any strain.
The pictures in the link show it being used to lift half rounds, but I usually can't rip logs until I get them home, so I am hoping that a tie down strap will hold a round in place until it is safely over the tailgate.
I made mine from 2x4 instead of 2x8 in order to cut down on the overall weight. It seems to be sturdy enough. The shelf is 2x8, and if I had been thinking, I would have made it twice as thick (for additional support), but I think this will be good enough. It's screwed, but not glued, so modifications are still possible. Will update once I have an opportunity to actually use it as intended.
Here is my version:
Dan