Pixie,
all I can tell you is "20mm of very high-tech shock absorbing foam designed for scientific instruments"
It's probably most easily obtained from companies that create packing/shipping boxes for musical and scientific instruments.
Personally I'd plan on backing up from the camera's card to at least two mediums. My experience and from what I've heard, the CF etc cards ARE very reliable.
I know of a number of people who have lost all their photos from one disaster or another - theft, bad processing of all their film, defective cameras etc - and listened to their tears and wailing and gnashing of teeth - to want to be very careful.
I'd probably back up to the laptop, and keep the original on the CF card and keep plugging in new ones, NOT overwriting the originals. Finally upload them to a photo site, and have a friend download them and save them to at least two places, my favorite being two separate USB hard drives. (CD's are NOT completely reliable, and they're a pain in the butt) THEN I might wipe the original CF cards.
FWIW - My backup at home/office (for EVERYTHING, including this entire website) is original on one of two different mirrored RAID drive set, backed up to the other mirrored RAID set, all backed up to two rotating USB hard drives. Overkill? Perhaps - but not if you've ever lost important irreplaceable files!
Remember - CF etc cards are dirt cheap compared to the loss of all your pictures, and the cost of the trip. Or even to the cost we used to pay for film. Take lots.
hope that helps!
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Grant Johnson
Seek, and ye shall find.
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One world, Two wheels.
www.HorizonsUnlimited.com