Gigabit Ethernet switch using Linux?

[Mike Fedyk <mfedyk@matchmail.com>]

Hi guys,

I've been looking at prices for a managed gigabit Ethernet switch, and 
thought the prices are a bit up there... :-/

All of the features I need could be provided by Linux, but the question 
is.  Can I get hardware that'll give me 12-16 gigabit ports in one computer?

Are there multi-port gigabit Ethernet cards?

I'm sure I'd need 64bit PCI as well as 64bit PCI cards to handle the 
bandwidth.

Anyone ever looked into this before, and have any pointers?

Thanks in advance.

Mike