Find a welding shop. They will make you anything you want.
^^^^^^
this if you don't have the means to do it yourself.
I made a hitch mounted lift for a guy that works on lawn mowers out of his pick up truck. It's a simple design. 3 pieces basically,
1) piece that fits into the hitch receiver and extends straight out as far as needed.(if you want it to clear the tail gate when it's down that needs to be taken into consideration when figuring how long it will be.
2), the vertical up right piece that will determine the over all height of the lifting range... You need to take into account any loss in lifting range taken up by the upper horizontal tube, a clevis mount, and which ever lifting tackle you decide use( come-along, chain fall, etc...)
The vertical up right welds onto the very end of the hitch tubing with the bottom remaining open. This way an adjustable "drop leg" can slide up and down inside of the vertical up right secured with a hitch pin.
3) a horizontal top piece that welds to the end of the vertical upright. It needs to be just long enough to give you enough room to work without the vertical upright being in the way. This piece will have the clevis lug welded at the very end of it to hook the lifting tackle.
I think I have pics of the one I built for the mower repair guy if Ph***bucket will let me download them.
The drop leg helps out a lot when weight is applied to the frame, but you can also put a ring or hook at the top of the vertical bar on the bed side of the lift. This can be used to run ratchet straps to the front corners of the truck bed to help with the work load and over all stability if needed.