Find the design here:
https://3dwarehouse.sketchup.com/model/a5c6c6b2-4dbd-4545-83fd-627451094d29/Cantilever-Sled-Deck
Special thanks to Cyrus Cosmo who's work inspired this one. https://www.youtube.com/watch?v=BKGFd5ONC2g&t=0s
Single sled deck, cantilever design so you can load your sled with one hand into your truck bed.
I made this under $500, the most expensive item is the caster wheels as they were custom from greyhub (crown tread). I'm sure stock casters would work, but the crown treads make it very smooth.
Note: to unload, you don't pull the deck all the way out, just to the pivot point (with pin in) and then release sled brake and it slides down.