Recommendations for compact, lightweight, waterproof hard case?

I want to take something bigger than my trusty Nikonos on my next canyoneering trip, but I'm having a hard time finding a suitable case for my LF gear. I'd most likely bring a Cambo Wide, extra lens, Kinematic back, light meter, a few filters, and small tripod. The case(s) would have to protect from bumps and abrasions from the rock walls, splashing water and short-term immersion. And because it will be riding on my back, it needs to be light, compact, and easily lashable to my pack. For the tripod I'd bring an old metal Linhof sans head, so that can get wet with no issues; the rest will have to be protected.

The typical Pelican etc. cases are waaay too heavy, and "dry bags" are laughable, in my experience. I've located the manufacturer of these dry kegs (http://www.summithut.com/products/canyon-keg/), and they're a possibility. They are strong and light and waterproof; their issues are that the opening is quite a bit smaller than the diameter, and that they go from too small (like the ones pictured) to huge without any intervening steps. The cylindrical shape gives it strength and waterproofness without much weight, even if it means some wasted space.

Any suggestions or products that I should consider? Thanks!

Light is relative, but if you have ruled out Pelican cases then check out these:

http://www.boundarywaterscatalog.com....cfm/4,42.html

http://www.boundarywaterscatalog.com/prodimg/D00485.jpg

Have you thought about a larger Rubbermaid-type container with a snap-on lid? You'd have to test it under similar immersion conditions, but it may work, even if you used a bag inside it.

http://www.amazon.com/Underbed-Box-Q.../dp/B0019O6FEG

Cheers, Steve

I remember a similar thread a few years ago. Someome posted a link to an aluminum backpack frame and strapped a pelican onto it. I thought it was brilliant

Below is an image just as an example.

http://www.kollewin.com/EX/09-15-11/nice_frame.jpg

Perhaps not discounting the Tupperware comment out of hand is valid... gear placed into a Tupperware container with some light foam padding, then the container placed into a series of several oversized ZipLoc Freezer bags... wrapped in a jacket or padded lenswrap, rolled into lightweight day pack, strapped to your larger pack. Seems like it would survive just about anything at least as securely as a Pelican case but quite a bit lighter... your penalty is making it more time consuming to pack and unpack for the lightness.

Check Lock&Lock plastic containers - watertight and some of them big enough to hold Contax 645 or ArcaSwiss 6x9 cameras.