You can do it at software level and here's how -
http://www.howtoforge.com/forums/showthread.php?t=1664
Confession - Haven't done it myself.
At hardware level it MAY be possible, depending on your hardware - I Googled for "raid mixed sata (ide OR PATA)" and found a lot of references.
Go SuSE!
Mac
PS: It looks quite a performance - hope you don't have anything else planned for the weekend!