Wow, thanks to everyone for the advice and ideas! Especial thanks to MarkF, med6753, Emo, and nctnico for posting pics of their solutions (and apologies to mods for the bandwidth, but I feel as though this is a constructive use of it, pun fully intended)!
You've all given me a lot to think about. It's true that there are very likely plenty of old Tek carts floating around in a spiral toward landfills/scrapyards here in the States, and I'll look into that option (although the shipping required may make it a little less than optimal; I don't exactly live in Silicon Valley, this is farm country). It did occur to me that "Hey, since most of the tech schools have switched to DSO's and PC-based solutions, I wonder if those institutions might have a scope cart or two repurposed as a bookshelf or something that I could helpfully switch out?" Yes, I'll be making a few phone calls tomorrow, methinks.
Awesome builds, guys. I'm really impressed with the spirit of innovation, improvisation, and resourcefulness I see around here on a daily basis.