Ive built a DIY mount for an older epson powerlite.
I cut a board [3/4" plywood] then afixed pencil leads in the screw holes on the projector to mark where holes needed to be drilled. I then went WITH THE PROJECTOR to Home Depot and found 2" long threaded bolts that would fit in all of the holes underneath the epson. I bought some rubber washers and some metal ones too. When I got home, I drilled the screw holes through the board. then I afixed wall brackets to the board. the board went up on the back wall, screwed to the 2x4's. then I had someone hole the projector while I lined up the holes in the board witht the projector and put in all the threaded bolts with the washers and whatnot. the rubber washers help fine tune the placement of the proj while keeping it taught to the board. it was a simple ugly solution but cheap and it worked.