Have you used OpenWRT?

[jonathan-Zp4isUonpHBD60Wz+7aTrA at public.gmane.org (Jon Masters)]

On Sun, 2008-12-28 at 20:59 -0500, Bill Horne wrote:
> I've been pricing wireless access points, and those that can serve as a 
> wireless client are much more expensive than ordinary wireless router/APs.

I've run builds of OpenWRT and DDwrt as transparent bridges, which is
probably what you want - you're looking to do the inverse of normal,
wherein you wish the "router" to expose a bunch of wired machines?

So yeah, there's one sitting in my living room/lounge right now.

Jon.