Just for fun on a Sheevaplug - add a powered four port USB hub. Inspired by the fact that a cheap Bluetooth dongle was recognised out of the box, I added a Netgear WG111v2 (rt8187 driver) and the Huawei GSM/3G E220 dongle to the hub. All were recognised in the 2.6.30 kernel and ID'd correctly.
Given that the Sheevaplug has GB Ethernet and the power to be a good firewall - this might make an ideal multi-gateway for an emergency / conference or whatever.
I haven't actually configured up any of the wireless interfaces - but all should work, though the RT8187 may be only 22Mb and may not support WPA2 - I can't remember.