WiFi can be added to some of their boards using expansion cards.

I have another one running in our firework storage container, it runs 2 expansion cards, one for WiFi and one for the 3G connection. I then run a VPN back to home so I have check my IP cameras remotely. All this runs off a Solar system that also powers the lights and alarm system, so it's pretty frugal on the power use. This is the one that runs in the container...

http://routerboard.com/RB411U

They are a great product and the idea is you pick the board with the features you want. They are used in mesh networks a lot, so WiFi is very much something they do.

Cheers

Cris