Good idea, Inferno (and Jazz)! Just might do this... I'd +rep that post, but I already repped your first post in this thread.
These are good thoughts, Kouen... I'm currently using an 8GB flash drive for my Wii. It holds around 4-5 "scrubbed" games, and works very well. The thing is, I've got 100GB+ of music, and am not always near my laptop to play it. However, there are good, capable MP3 player softwares written for both PS2 and Wii... thus, my thought of having my external HDD formatted so my consoles could read it.
You're right, PS2 USB-loading isn't great. The only PS2 game I used to bother loading from USB was "The Adventures of Cookie and Cream" (no FMV to stutter, all scenes remain in the game engine). Results with that one were good... speed was not much slower than loading from disc. Other games? Not so much.
Thanks for posting. +Rep for your time and info.