Have you seen the "Redpark" ethernet adapter for the iPad? I'd like to try it, but it's expensive (~$60 on two websites). When I travel with my family, we have several iOS devices. Unfortunately, hotel wi-fi internet access is always locked down to one device (locked to its specific MAC address). This means I have to pay $10 per day for EACH DEVICE.
With a laptop, you can connect to a portable router & clone the MAC address to the router. Then the router can act as the wifi source for EVERY DEVICE. (This would allow $10 daily wi-fi, no matter how many devices you have.) Unfortunately, the Airport Express does not support MAC address cloning. I'm told the "D-Link 1350" wireless router does support this, as do many others. But without a laptop, you don't have an interface (via ethernet) to the router in order to accomplish the MAC address cloning step.
Perhaps with this Redpark adapter, you can get this working -- even without a laptop. Anyone every try it?