Really? I've come across dozens. Even going back to a game like Halo 3 was a total bastard to play in 4:3.
Admittedly, I don't play too many different games (not much for FPS or platformers, e.g.) so I certainly can't say that there aren't any others that don't support 4:3, only that I haven't seen/played any. (All of the Assassin's Creed franchise, e.g., has supported SDTVs.)
This generation of consoles was not designed to work with the previous generation of TVs. You can TRY it, but developers haven't been supporting it for years. I don't think it's a requirement for Submission at Sony or Microsoft any more either.
And what do you mean the 360 wasn't designed to work with CRT and 4:3? When it launched (2005?), standard definition was, well, still the standard. Most broadcasters at that point still broadcast in SD and HD TVs were still relatively expensive. The first 360 model to have an HDMI output wasn't, I think, until 2008. Ironically, I bought my 360 (hadn't had a gaming system for a number of years) late in 2008 specifically to play Oblivion (on a lark I'd rented it while housesitting for my sister who's kids had a 360).
And lest you think those still playing on SDTV's are a tiny minority, most of the families I know with an xbox in their household have a seperate TV for their kids to play games on, and guess what kind of TV most of these kids have to game on? That's right, the SDTV that got replaced by an HDTV for their living room.

But just to reiterate, I'm not slamming Bethesda. I know SDTV is now officially a past generation and I don't blame them for spending their time focused on the current generation. It's a beautiful game, even on my SDTV. Someday, it'll be like playing it again for the first time when I'm able to play it in its native HD.
