even for ipad2, the storage on the device is also limited, no? wouldn't it be better to buy more cards instead?
calculate how many photos you shoot in 1 day. multiply it by 25MB (Raw file)
then multiply that by the total days you're going overseas. then you'll know how many 32GB / 16GB cards you need.
example, if you know you're going to take an avg 500 shots per day.
500 x 25MB = 12,500 MB (~12.2GB since 1GB = 1024MB)
if you're going away for 5 days;
5 x 12.2GB = 61GB
that will take like 2 x 32GB cards? maybe can bring another 1 more 32gb just in case.
if you're using sd cards, the cost of 32GB cards have dropped quite a bit. at the it fair, a normal class4 32GB cost about $35-$38.
cf cards probably cost more.
this is still cheaper than buying a portable storage device.
Unless you have dual slots on your camera device, the main worry is the card will fail, usually.
I myself have an old portable storage device with a measly 20 or 30 GB of space... I don't really care about upgrading this because I just want to keep another copy to ensure that if anything goes wrong, i.e. camera goes into the sea, card fails, I still have pictures from my trip as those are worth more to me than the camera or the card.
But of course, if TS just wants to make sure that he can have enough space to shoot during the trip (how so, I don't understand, I can never even fill up a 8GB card even with family snaps)... Then I agree with your assessment that it's more worth it to buy more cards.