Who's this Joy cat in the mic business

?
Anyway...getting the ribbons, even if they are corrugated is only about 1/4 of difficulty of re-ribboning a mic. This work is sort of like learning to play an instrument - there is no substitute for practice, errors and iterative corrections during installation and tensioning.
If you do a search you'll find the tips I've posted for slicing, corrugating, installing and tensioning to proper resonant frequency. But reading these instructions is no substitute for handling 1.8 micron aluminum. I don't want to dissuade you, I totally support DIY, but believe me, you'll need to do this a dozen times before its close to right.
That's why ribbon mics have been traditionally been repaired by experienced practitioners with materials, tools and techniques acquired over years of practice. But yes, you could re-tension a slack ribbon in an evening and not break it if you're careful. There is a guy on eBay who sells corrugated ribbons I think. But this is a bit like selling parts for a mechanical heart. Yep, there will be people from Chance Pataki's group buy will will be installing their ribbons any time now. Will they nail the resonant frequency? Maybe.