Rob, yeah I know it's sole and not soul, just a Freudian slip so to speak ;\)
When I mentioned SuSE in my previous explanation it was because SuSE allows for a internet based installation where you only install what is needed ans not a thing more. Has nothing to do with the distro itself. Apart from that Lonk and I usually have these type of discussions, we both are right but we love to split hairs ;\)

Lonk, you know as well as I do that when I mention a "full OS" that I mean the basic installation of the distro media. I know we agree, I just disagree with how you read it ;\)

Btw, since we're on the subject, there are a lot of VMware Appliances nowadays that cover the role of firewall with minimalistic OS's even smaller then the "hardware firewalls".
I'll call them Virtual Firewalls for now that don't have the CPU/MEM boundaries of the hardware variants ;\) But the downside is that you have to configure your Hardware internet access to get to it NAT/Open ports etc. ;\)