Storage Help: 10 days of Canyoning with my 40D!!!

In Sept 2008 I am going canyoning through remote Northern Western Australian gorges and intend taking my 40D, a wide angle lens (Siggy 17-70mm) and light $50 tripod.

Anyway, I'm going to be abseiling 60m down waterfalls, into water, swimming 4km at a time and walking over rocks in dusty conditions. I have to carry all my own gear and will not be taking a dedicated camera backpack.

So what's the best way to protect my camera? I'm thinking of some pressure seal box, or a gortex bag of some sort. I have a Gortex sleeping (bivvy) bag that I will use as a pack liner as an initial level of protection.

Any other ideas?

Pelican or if you won't drop it a dryzone

but maybe a Pelican inside a larger backpack that is multipurpose

I've done quite a bit of hiking with my 30D in crappy weather with the camera in a neoprene OpTech case and a smaller drybag, like the types you'd find at REI or other good camping/kayaking stores. I haven't had any problems with this kind of arrangement so far.

I'm doing a couple of wet canyons this weekend and I'm really agonizing over
whether to take my 40D or not. I've got a few dry bags that would probably work, maybe a large Zip Loc inside a good dry bag.

You would probably not want a Pelican case inside the pack, if your rubbing on rock walls it could cause holes from wear.

I'll report back if I carry it and if my system worked. My option is my Olympus SW770 that's waterproof!

Win

Thanks for the excellent information all ... I've already been checking into all of your suggestions. I'm keen for more tips as they will help me choose the right gear and will let me post some great images from a dry camera!

Win: please let me know what you carry in the 30D, the conditions and whether what you get does the trick.

LowePro Dryzone Rover... I have the Dryzone 100, but that holds a lot more gear and is bigger, without the room for "personal items" like the Rover.

I decided not to take my 40D in the canyons. It was a good decision for me ,
the canyon was cold and very wet. I would not have taken any pictures. I had my Olympus and didn't even use that.

A friend did have a medium size Olympus (not 40D size) and had it in a padded camera case and then in a dry bag. She kept the dry bag clipped to the front her pack and the system worked fine. She's very experienced at canyoneering and I'm going to try this system at some point.

Win

Keep the ideas coming, they are useful for me and everyone reading.

My trip will be be dry desert canyons apart from a few abseils down waterfalls, a 4km swim and a 2km swim the next day it will.