http://www.steelheader.com/

Check these out. They aren't cheap, but they're capable of handling pretty much any water you are capable of rowing.

Check the archives using "pontoon boats" or "catarafts" and there are lots of past discussions.
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She was standin' alone over by the juke box, like she'd something to sell.
I said "baby, what's the goin' price?" She told me to go to hell.

Bon Scott - Shot Down in Flames