My only thought would be to try the salvage yards. That sure is a nice replacement battery box though. I'm guessing most of that cost has to cover all the FAA paper work to make it "legal"
N8395M 1970 A150K The Carolina Swampfoxes founding member I've landed my Aerobat in the following states:
They patch corvettes all the time. What you need is an A&P with an AC 43.13-1A, to show you how lay glass. A trip to Autozone or NAPA and some glass mat. Shawn
Ive got a 150 battery box in very good shape, no holes or corrosion. Clips in place. Take a look at the salvage sites etc. Let me know if you are ok with 200$ for the box and lid. Needs to be cleaned and repainted.