hi there...
just starting also to get mobile and still looking with what VJ app I'll work. did all the time work with the equipment from my partner and my tuned AGP G4
I've now bought the 1.67 Ghz powerbook with 128 MB ATI ... it's the best computer I've ever own and the keyboard-light is perfect for vj-action.
when 10.4 is released, I guess Modul8 v2.0 will be my choice...
concerning RAM for the pb, in germany a very good partner is dsp-info, who have good service, good prices and stuff that's meant and tested for macs ... here's the link: www.dsp-info.com
shouts
dUb