Just out of curiosity I installed the Linksys WRT54g userspace distribution on my parents’ WRT54g, and found it quite entertaining to browse around.
Interesting aspects of it:
– it runs an embedded ASP-capable httpd, which actually appears to be a customized ASP dialect (I don’t know why they didn’t use PHP or Tcl instead)
– Linksys didn’t actually write the code; it was done by a company called CyberTAN
– This amusing notice appears in the top of it:

This is UNPUBLISHED PROPRIETARY SOURCE CODE of CyberTAN Inc.
the contents of this file may not be disclosed to third parties,
copied or duplicated in any form without the prior written
permission of CyberTAN Inc.
This software should be used as a reference only, and it not
intended for production use!

CyberTAN doesn’t deem it necessary to follow the LFS, and I have no idea where the inittab (if any) lives.
There is a tftpd instance running all the time. No idea why.
It also has a daemon for listening to the reset button. Which means that if the device were to crash, the reset button probably wouldn’t do much good…
Also, the Linux user tools distribution opens up the telnetd port to the entire world, and of course there’s no user auth on it. Not that a kiddie can do that much with a root shell on it anyway, but still.
Anyway, somewhere in that ramble I forgot how this had anything to do with the IPv6 stuff, except maybe I was going to say something like how it’s conceivably possible to install 6to4 on it yourself or something. But oh well.