Just checked out the idea from Micah McDowell and that would probably be your best bet if you don’t mind tinkering with your Mac book Pro, at the moment there is a free case that ships with the new drive that you put your removed ‘Superdrive’ in to and don’t loose the use of the CD/DVD. Looks like a really good idea, no idea if it works though.
Personally I have a 2TB Quad GTech external drive connected using a Sonnet Tempo SATA Pro Expresscard/34. This setup is very fast at doing most things you would want to do ‘on the road’, I’ve been using Apple Pro Res 422 media (that was originally ‘log & transfered’ from RED files) and is faultless, no lag/ freezes. The one downside of this setup is the fact that you loose the use of the Card 34 slot on the Pro but there are ways round this.
buss69