I hadn't twigged to the depths extent of your costume-love; just the Faire associations.
Last week I spent time searching men's Victorian-era underwear- 'cos it underpinned cowboy [1890s] gear, and *not everyone* wore union suits!
Whilst searching, I found some nifty pattern sources and info on corsets- women's, and, yes, men's [but I don't plan on any personally]. Alas, I don't sew, so have never done anything but pull together ready-made items.