Tyvek 1443 is a brilliant fabric for rain pants.
It's very breathable, and way more durable than you think. I hacked together a pair and bushwhacked in them pretty hard. I was totally impressed.
Where are the cottage manufacturers when you need them? :D
T1443 pants would be far more useful than DriDucks, Frogg Toggs, and Cuben Fiber and Silnylon pants / chaps / skirts.
Oh, and yes, Frogg Toggs/Driducks are among the most breathable things out there, and just fine to hike in. Same w/Tyvek 1443.