I think if there is enough of you, you could get a good deal on some laser cut arms, get someone else to ream the holes out and you'd have yourselves a nice setup
There's a .pdf of a JD2 type bender build here which is an interesting read. He uses hole cutters and grinding disks to cut the arms and drill the holes, none of that expensive laser cutting Here is a bender .pdf showing the parts.
I was in the same situation, I had plans "off the net", but wasn't happy with the validity of measurements, I'd hread good reports on the Gottrikes plans so I bought them they only cost a tenner, and Frank gives lifetime email support. The plans come as a locked PDF, so if you pass them on he knows where they cam from, and to be honest what's a tenner.
I didn't want the style of bendr of Got trikes so took the measurements and built a standard setup. Works very well, and the bends are perfect. I also based my decision on franks bender using Protools Dies, I read horror stories about JD squared customer service, and nothing but good reports about ProTools. so that was my mind made up.
As for Hydraulic I spoke to Jim at protools and he explained the only reason they use 10ton kits is they are far cheaper than the 2.5ton kits required to bend the largest tube. If I can be of any help just let me know
PS, I wouls strongly advise not using hole cutters or the like to make one, the quality of the bends depends on the build quality and fitup. Laser and milling IS the only way