The PXA270-based Zaurii would max out @ ~200mA (+5V) supplied to USB OTG clients. Good luck finding a dongle with such a little power consumption that has Linux drivers available and would play nice with OHCI host.
The output current power limit on OTG connector can be increased by replacing a resistor on Z's pcb, but it requires some soldering skills, and also puts the Z out of the warranty.
Having said that, I have a C1K with resistor replaced, and my internal wi-fi module works great. Also, I have tried two different prism3-based usb dongles which work with wlan-ng drivers.
-albertr