We don't have one that we normally recommend. If I had to guess, I'd say to stick to one of the bigger names in expansion cards. ADS, Belkin, SIIG.
But that being said, we have not tested them.
Most of our users just buy a powered USB hub if they run out of ports.
If you have devices that have to be hooked up directly, hook them to the Creation Station, and then put your keyboard, mouse, dongles, and other low bandwidth devices onto the hub.