quick notes. Ultimate joysticks aren't the preffered. Read Oscars site and his review of the different happs joysticks. Very good review.
Also, instead of all the USB ports, go with an IPac. 40 bucks and you don't have to deal with taking 4 usb ports and buying 4 controllers. (unless their free of course). You will be VERY happy with the ipac.
many many of us started hacking somethign and moved to an encoder later. I think hacking is a good start. But your setup sounds like you wont be saving that much cash, so you might as well get the good stuff.