No idea how ORB works, however routing network traffic from bluetooth via a wlan connection works well for me. I compiled the kernel with iptables nat support, recompiled/packeaged the iptables package to include some needed libs and setup simple masquerading rules to forward the traffic. That way I can use my umts flatrate via bluetooth from the mobile phone on my n800 while also providing natted network connectivity to my girlfriends n800 through an ad-hoc wlan link. I think the tricky part was just getting the ad-hoc connection active without shutting down the bluetooth link to the phone, some iwconfig/ifconfig scripting solved it. I have old modules and a iptables package on garage.maemo.org, the current modules are still under test but about the stability no complains came up yet I will update the files on garage.maemo.org asap, just updating to the latest OS release.