My Linear Limo, sold a couple of years ago.
I added the tube for the top run of the chain (earlier linears had an alloy guard), changed the Q/R steering rod ends to proper aviation rose joints and had a few bits anodised that were bare alloy. I found that loose rat traps worked well on the pedals. I think I did about 2000 miles on it but still remember when the steel bead of a new rear tyre failed after only a few miles and locked the rear wheel solid while going down a hill…….
One big advantage was that I never felt that it would be stolen. OK, I never left it in the centre of a town, but compared with a normal upright no one was ever going to jump on it and ride off.