Don’t panic
I’ve found a solution to my woes. And it’s not a bridge! Well it won’t start life as a bridge, at least.
My plan is to spend less money on a Linksys WRT54GL, and flash it with some nice 3rd-party firmware. I’ve used this device in the past (albeit in its original 54GS v4 incarnation) and I regard it as the best Ethernet router student money can purchase, particularly with the features unlocked in it thanks to the world’s hackers.
By roughly following this guide, I intend switch the wireless access-point functionality off and instruct the device to act as a client instead. Once this is done, I’ll be able to share my new wireless connection with up to 4 devices via the built-in switch, and Linux may never know I’m using wireless. It also goes without saying that the antennas supplied shall be much more powerful than any wireless NIC (you can even boost the power to illegal levels, should you feel unnecessarily anarchistic.)
The only issue comes with having two steps of PAT, and thus two seperate networks. I don’t envision too many issues with this approach (besides having to forward any outside ports twice) but I’ve got a feeling that it is possible to switch the PAT off and let some true routing to go on. I’ll still be behind the gateway router’s PAT, so there’s very little at stake security-wise.
And I’ll still have to route between the two networks, but we’ll see how that goes.