Can anyone suggest a possible DIY fix? Otherwise I'm going to have to decide between getting an N800 and waiting for the rumoured new Mac sub-notebook...

I believe Thoughtfix had a take apart howto on is blog. I don't remember for sure now, should be able to search for it here. I don't remember if they plugged in, or if were soldered, but it's worth a look. It'll pass the time before you decide to get the new one, or even after you order it.

Does bluetooth still work? If it does, then there's probably damage to the wifi circuitry. If not, it could be an antenna problem.

In thoughtfix's pictures, it appears that the antenna is mounted on the case and connects to the board with a spring contact. I have not taken my own 770 apart, so I could be wrong here. The spring may have been bent so it doesn't contact the board anymore.

Thank you both. Sadly bluetooth works just fine. Do they both share the same antenna?