The OP didn't ask about recovering originals in iPhoto on the desktop.
The OP specifically want to use the iPad as a traveling device, much like a Macbook would be used, to offload pictures from a camera while traveling.
The answer to the OP's question is NO, you cannot currently use the ipad as a backup device, and when the camera adapter comes out one can only hope it works the desired way, but I have my doubts.
I have an iPad and desire the same thing as the original poster.
I took 16GB of iPhoto desktop photos and iTunes tooks 2 hours to transcode them in order to transfer them to the iPad, at which point they only took up a couple GB on the iPad.
I only hope that the Camera Dock for iPad works differently, preserving the original.
My doubt is Apple would have to do the right thing here-- when plugging in an iPad containing full resolution pictures on it in, the iPad must simply pretend to be a camera and iPhoto should pop up asking if you want to import the pictures as usual.
We shall see. If anyone knows how the original iPod Camera Dock worked, that might shed some light.
The ONLY thing holding me back from getting an ipad is the question of how I can use it to backup photos on vacation.
So the question to anyone who has one, is there a way (and how) to backup SD or Compact Flash cards from cameras onto the Ipad?
or if not directly to the 64GB memory, can you use it to backup to your online apple idisk storage somehow? or other online storage places etc?
Thanks!