Linksys produced hundreds of these routers for Rogers and T-Mobile for a voip project that was canceled. Both are essentially the same as the WRT54GS v3 (they have 8 MB flash and 32 MB RAM) and thus can be loaded with the WRT54GS v3 Broadband Hamnet firmware. Many of these Rogers routers (in Canada) and T-Mobile routers (in the USA) can be found still sealed in the original packaging.

A zipped file with instructions and all required files to replace the original firmware with bbhn can be downloaded from: http://ve3rrd.ddns.net/files/Broadband-Hamnet on WRT54G-RG and TM.zip

The TRX file to upgrade existing Linksys bbhn routers to bbhn-3.0.1 (zipped) can be downloaded from: http://ve3rrd.ddns.net/files/bbhn-3.0.1-brcm-2.4-squashfs.zip and the procedure to add the new tunneling solution to Linksys routers with 8 MB of flash and 32 MB of RAM can be found at: http://www.broadband-hamnet.org/documentation/204-the-tunnel.html 

If you are using these routers as a tunnel server or client, you must also include the "bug workaround in hotplug" fix discussed here: http://www.broadband-hamnet.org/hsmm-mesh-forums/view-postlist/forum-5-problems-a-answers/topic-1527-vtun-tunneling.html 

And to add a count of Remote Nodes and Current Neighbors to the mesh status screen, replace the "/www/cgi-bin/mesh" file (chmod 775) with the one given by K5KTF at: http://www.broadband-hamnet.org/hsmm-mesh-forums/view-postlist/forum-3-firmware/topic-1538-wrt-mesh-status-page-update.html#ccbp7070