It might be less expensive to buy a used fork lift - my dealer uses one- or a used tractor, both of which can be readily adapted. The tractor could also be used for many other things.
Putting anything on the jacks, which are designed for only up and down motion, and and subjecting them to horizontal stress could cause major problems, IMHO.
Elliott, Vicky, and Sadie, our GSD
2014 Redwood36RE Titan Disc brakes, 17.5 " Sailun Tires
2013 RAM dually, CTD, Aisin Tranny, CC, LB 4x4