The current project at work is to convert a Cobalt RaQ4 into a firewall for the new office. On the plus side, it's an x86 based system, 450MHz with two ethernet ports, 256MB of memory and a 30G of disk space—more than enough to act as a firewall system.
On the down side, it comes with no CD drive, no floppy drive and no video or keyboard ports.
On the scale of Unix installation difficulty, this rates around a 6 (the NetBSD install I did rated about an 8, and a Unix install I did on an old laptop was about a 9). And while there are some instructions on installing a new distribution of Linux on the Cobalt RaQ4, they all are somewhat involved.
I was able to get a Linux 2.4 kernel on the system (albeit it's a custom kernel for the Cobalt systems) so that's good (it also involved an upgrade to the BIOS to support the larger Linux 2.4 kernel). And it seems that all you have to do is put the kernel into a specific location with a specific name and it will automatically boot that kernel, which is good, since that means I can put the drive into another Linux system and do the install of whatever distribution we want on that, and put the drive back into the Cobalt RaQ—in theory. I'll find out if that works on Monday.