I've installed an app called BlueVPN on my Nexus 7. As far as i can tell it doesn't do anything VPNish, but it uses my N900 as a bluetooth modem {DUN}. So even without WiFi I am able to browse and reply to this question

After fixing the USB port and now the ability to be used as a bridge between Nexus 7 and the interwebs there is no reason to abandon my N900.

Just now I notice something funny. Browsing and using an ssh client works fine. DrawSomething complains that there is no network!