Thanks. We've been making spreadsheets already to try to figure out costs, potential profits, pricing, etc.

Weirdly enough, the ultimate backup plan is to make jewelry since a lot of the tools for making brazed steel bikes is the same as for working on jewelry. My friend and I have dabbled in jewelry as a hobby so we figure we can at least make the shop rental pay for itself with some jewelry sales if the bike business is a total flop. We definitely want to make the bike thing work though.