I had a Tech III until I upgraded to a V. The upgrade was mostly prompted by the additional front movements, which honestly can be accomplished in other ways. I mostly wanted a newer camera that would be reliable for a long time into the future. If an affordable opportunity had not presented itself when it did, I would still be happily using the III.
I disassembled the rangefinder on mine to eliminate parts that were making closing the door more difficult. I left the housing on the side since I did not want to replace the leather. Someone...Jim Galli maybe...showed off a Technika that he had removed the leather from, and just left with the polished, bare metal. With a new red bellows it looked really great, like a Paul Teutul chopper! Might still be some pictures on the LF forum.
Regarding lens boards, I made a couple out of aluminum plate that I bought at a home improvement store. You will probably have to stick with a Linhof lens/shutter made to stay on the camera while folded if that is what you want.