Can the Wi-Fi 101 Shield be set up to be an Ad-Hoc network where the SSID is set as the network name? Normally this implies a DHCP server too, but the address can always be set up static.
I have an application where the Arduino will be a Modbus relay. User's can walk up to an array of sensors on a RS-485 bus that are wired to the Ardunio and get readings with a laptop, IOS or Android device.
There may be no other network or access point to connect through.