Hope that helps.
As far as firewall, I have made a conscious effort to NOT comment of existing firewalls, as I created my own. I took an old P120, installed a minimal distro on it (Can't remember it offhand), and manually edited the ipchains file to drop all connections coming in that I did not specifically request.
Nobody ever gets in, and I can get out. It took me about 4-5 lines of code.
As far as a lightweight distro, try Puppy Linux. It contains a fairly decent set of software, and it's a popular distro.
I just remembered--I've heard pretty good things about Devil Linux--a distro made for firewalls and routers. I have had no experience with it, so I don't know how it works, I would doubt that it will work exactly like you are used to, though.
Again, thanks and feel free to send more info that might be relevant anytime you come across it.
Cheers!