I hear what you're saying about water proof being hot, but that is what I deal with now. My current boots make my feet sweat, but they also get wet. So if I have to choose, I'll take a little sweat. Those waders are pretty cheap, and I bet they are light as well. I've never had to cross anything requiring waders to date, but they are on my radar.
I've heard of Irish Setter, and the price and lightness is pretty attractive.
I did a search on here about boots a few days ago and one of the work boot threads was saying that the Army Navy Surplus store has a pretty good selection. It's been a while since I've been there, and remember that they had a ton of boots, but do they carry quality stuff? Being able to try on boots, and cash and carry would be awesome.
Keep the suggestions coming.