Maybe a stupid question...
Nah... but I might have a stupid answer for you...
(Or a question or two, myself, if you prefer.)
Searching Synaptic for the word "router", I discovered dynamips and dynagen. It would seem, if I'm reading correctly, these would allow one to create a "virtual Cisco router"? (That only looks to be useful for those who are studying for a CCNA, though...
Searching for the word "network" finds a whole bunch of networking and network management tools, but it would be beyond my rudimentary networking skills to know how to set up an effective router with them. (Maybe if I noodled on it in my copious free time?
(See definition no. 1, please.)
While it might be worth searching the fora to see if anyone else has done it already, probably the best, ahem, route to take to get there is to use a distro specifically set up for that purpose. There's a nice list
over on Wikipedia that seems like a good place to start. (I remember playing with a few of the distros listed a while back...) Maybe looking at how one of these does it might yield some insights into how PCLinuxOS could do it?
Just a few random thoughts from a mind recovering from jet lag (rotating shifts).