I called a local pet store, and they said they carried a 40gal rimless for $170. I wanted to make sure it was the 40 breeder instead of the 40 long, so I asked how wide it was, and she said it was 18" wide (okay, good) by 30" long. Huh? They were closing, so I didn't take the time to clarify, but I'm hoping she just misspoke. I can't find any tank size, standard or otherwise, with a 30"x18" footprint (or even with 30" and 18" dimensions in any direction).
At any rate, that's cheap enough that I'd definitely be able to budget for a rimless tank. Fingers crossed! I'll call them back tomorrow for clarification.