In reply to h.cook2000:
Depends on the trad rack...
I'm sure the classic UK rack would be fine (2 full sets of nuts, a few cow bells). But dessert rack would not (doubles on all sizes cams, plus triples on C4 0.3 to 3).
Back to business, I'm using a DMM Vector, Ikea bag and 60l haulbag. For summer, they all work just fine. For winter, it get's a tad crowed (often need to fasten helmet outside, as well as the big belay puffy).
For generic craggin', I'd look into the cheapo Simond, DMM Flight and BlueIce Octopus as an all rounder. They all should fit in as carry on, on planes... and about fit all sport climbing stuff. Trad stuff should also fit, especially if you can lug the rope out side.