It's got a decent amount of tools already in the AUR(Arch user repository) and people seem to be taking a liking in helping add more tools. Arch Linux being bleeding edge, I figure it can't be that far behind Backtrack in new tools (except backtrack scripts which have to be ported). There is not yet a live-cd/usb version yet, it's on the roadmap though, but if you have arch linux (I would recommend you try it) you can install these tools on your current arch linux distro.
This just works out for me personally because 1) I enjoy being able to do everything from one OS without a reboot. 2) I can choose the best tools I see fit to help me pentest. I don't need 6 DNS enumeration tools, or 5 different aircrack-ng wrapper tools. I just need the top 2 or 3 tools for each categery/sub-category (information gathering/dns)
Just though I would share this with you and maybe get some of you to join in on the package making fun!
post-script: Although there are meta-packages archtrack(stable) and archtrack-dev(svn,cvs,git,etc.), you can still install the tools individually.
eLearnSecurity Team Member.