I missed this thread earlier in the year and while I don't have anything to say about the TA rack besides "really cool," I will add that a brake booster can be made out of a stainless sink drain flange. Or thrust washer, or whatever it's called. I'll see if I can find my spare and attach a photo. My Weinmann center pulls on my Miyata 610 use a pair of these home brewed boosters. Chop the ring in half, Dremel off the sharp bits, drill two holes where the brake pivot bolts go, and add longer M6 pivot bolts.
As for the lighting issue, feel free to take some ideas from here:
1964 A.S. Gillott "Alpine Tourist Deluxe", Ron Cooper brazed. Build thread.

Phil