If you can find a (non-LinkSys!) version of the OEM Realtek 8181-based wireless router/gateway/access points, then they all have that functionality, including WDS mode, in the OEM firmware.
The "Network Everywhere" NWR11B model, made by LinkSys, is also an OEM Realtek 8181-based platform, but they apparently deny even the existance of this product, as it is no-where to be found on their web site, and haven't released a firmware upgrade, ever, as far as I can tell.
I'm still in the process of trying to figure out a way to force the flash of some other OEM's firmware, in order to enable WDS support. I bought mine as part of a kit that also includes a Cardbus 802.11b adaptor at Wal-Mart for $50, they are on clearance, if you can still find them. Theoretically, assuming that they can be alternate-flashed, these seem like decent units. They sport a 200Mhz MIPS-based CPU, just like the LinkSys WRT54Gv2 units, and run Linux. (Yes, LinkSys and Realtek are violating the GPL here, because the full source still isn't available to the public from either of them.)
Even if the flash is possible, I still don't know if the Realtek WDS mode will "talk" to the Sveasoft WRT54G WDS mode. But that is my eventual goal.