Help: UW bag

Going to Thailand in 2 days and I thought I'd invest in a cheap underwater plastic bag for my 5d2. Not going diving with it, just want to bring it when kayaking and snorkelling. I want to be able to use it with a 15mm fisheye and perhaps my 17-40.

Ewa Marine has lots of UW bags but I'm not sure which would be suitable for the fisheye. Any suggestions?

I wouldn't... At least not with the 5D2.

It might be ok at protecting against splashing when kayaking but I wouldn't take it in the water. One little leak, and these bags have been known to leak, and your camera is toast. If you want something for snorkeling, Olympus makes a waterproof (down to 30 feet) point and shoot camera. That would be a better solution for you.

There are several people that use the 5D2 in such a housing. It's risky, yes, but it should be fine as long as one is careful. And as I said, I wont go diving with it, just surface action.

What about the fisheye, is it too wide for anything they've made? I can't find any information about that.