So I got the
Delkin USB 3 reader. It's a cheap piece of plastic, and came with a ridiculously short cable (with micro-B connector on the device end, not something I have spares of laying around). But it's fast; I got a sustained 68MB/s download from my PhotoFast GMonster CF card. That's more than twice as fast as the Sandisk FW-800 reader I was previously using (it died), and even a bit faster than the ExpressCard reader I use with my laptop.
I still question why somebody doesn't make a fast eSata card reader, since right now there are probably a lot more people with eSata ports than USB3 ports.