On my new computer's motherboard there is no Ps/2 port. I discovered this when I tried to plug in my beloved mechanical keyboard. Is there anyway that I can add one (e.g. expansion card or breakout cable) that does not make use of USB? I am aware that there are a plethora of usb adapters out there but NONE of them support n-key rollover (which is a deal breaker for me).

Never mind I found a hardcore solution: http://geekhack.org/showwiki.php?title=Island:17458