I have never seen a combined USB hub and 100BTX switch but that doesn't mean they don't exist.

With USB 2.0 High speed devices, they are able to operate at all three USB speeds (1.5/12/480mbps) so buying a USB 2.0 HS hub now means it will work at 12mbps fine now with your 1.1 host, and when you upgrade you will get the speed improvement without needing a new USB hub.