Back when I was doing lots of pre-release demos of Smartphone I used to have to carry multiple developer kit phones, batteries, and debug boards. There's nothing quite like packing circuit boards with LED displays on them, especially after Sept. 11...
My carry bag of choice was a
Plano fishing tackle box. Lots of little compartments I could split up into little sizes for batteries, MMC cards, tools, etc., and then bigger compartments for the phones and debug boards. If security needed to search, a couple of quick flips of the catches and it was all there for the guy to see.
The folks at SEA said "oh my, I hope that isn't fishing gear". The folks at LHR didn't even bat an eye or ask to open it!
I also learned on my last trip that HPCs (remember those?) are considered laptops, and you gotta take them out for screening outside of your bag.