^^Those guys have it for cheaper. And in my experience, their service is at the level of or better than newegg's.
The limiting factor would indeed be the number of PCI slots. Back in the old days, they had parallel port switches/splitters. They would take one computer port and wire it to a switchbox with four or so outputs. You just flip the switch for whatever printer you want. You might be able to find one of these on ebay or something.