Since WEP is essentially the same as no security at all, I'd like to know if there has been perhaps a firmware update to make the DS worth plugging into my lan.

First thing I would do is hand check the WEP key being generated in linux to the key on the access point. Using linux-wlan I had to use an alternative key generator.

Still a stop-gap solution was developed – using WEP with 802.1X to cycle WEP keys automatically. By doing this, any single WEP key wouldn’t be in use long enough for an attacker to crack it.