Navizon isn't so much about true WiFi, but using the cell ID provided by the cellular networks for a mobile phone to provide rough location.

However, thinking this through, I'm not sure whether mobile phones can provide the cell ID information via a Bluetooth connection, so it may still require the Navizon client on the phone to calculate the information, and then the Geoclue Navizon backend would simply need to access the client on the phone somehow to get the position, and then provide it forward.

It might be worth asking Navizon whether there is any way to access the client directly - I know there is a way to access it - you can publish your location via an XML feed for use on the web - maybe a Geoclue backend could be written to access this over the internet to provide the information...

Certainly most people who carry a 770 / N800 will also have a mobile phone with them, so somehow being able to utilise the mobile phone network as a location information provider makes some sense to me.