USB2.0 wouldn't be too fast for the empeg's CPU; Yes, we wouldn't be able to saturate the bus (by any means) but we would be able to go faster than 10mbit ethernet without a doubt.
We don't use the SA1100's USB controller, we use an external one. Why? Because the SA1100's USB slave has been severely bugged for a LONG time, and most/all of the SA1100 silicon we had in stock featured the bug. The Mk1 used the Natsemi USBN9602 (arrrrgh, never again, big EMI issues + hardware bugs) - the mk2 used the Philips PDIUSBD12 (bugs & very twitchy about timing). On the mk2 you can remove/fit some 0-ohm resistors and switch the USB to the internal SA1100 if you fancied it, but if your CPU isn't one of the Intel branded ones, it won't work at all. If it is an intel branded one, it won't work if you have more than one USB device on your entire USB subsystem (or so the errata says).
Basically, no, it won't be "reworked". USB 2.0 is a different kettle of fish to USB 1.1, you can't just twiddle something and have it work - you need new silicon and a new PCB layout.
Hugo