If you have a bluetooth usb transceiver + keyboard, then you can load the bluetooth kexts on boot time. Then you have to install irkeyboardemu. This will allow you to navigate through frontrow via keyboard. I think, then in couchsurfer you can use it to enter text, eg. into the google search field.

The irkeyboardemu, imho, doesn't work on ATV version 2.2+.