I've been using hard drives in caddies as you have to a long time. Only nuisance with PATA is the need to shut down and reboot when changing.
If your new mobo doesn't have PATA channels or you're already using them for CD/DVDs then you can get a slot-in PCI card that will give you at least 2 master/slave channels.
Lots of 'em around, just google for 'em
