From what little I've found it sounds like the only way to fix this is to send it back to Nokia, but I guess I could be overlooking something.

There is no wifi icon at all (unlike 3g, gps, and bluetooth.) Wifi networks do not show up (all power savings turned off.) wifi apps do not work at all. sudo ifconfig|grep "wlan" returns nothing. It's done this since the beginning, and persisted after installing a custom kernel, etc.

Is there something I'm missing here? Some big master switch to 'turn on' the wifi ? I only have a few days left if I want to RMA this thing...

only thing I can suggest checking, you're not trying to spot a wifi access point on channel 13 are you ?

you could be set to only see channels 1 to 11

unlikely, but worth checking I guess.

Have you tried a complete re flash ?