I know a lot of people hate the stuff, but Lion Brand Fishermen's wool is a good wool. Sturdy, little to no pilling. HOlds up very well over time, doesn't lose shape. Softens with wear and washing. Not great for heavy wetters, but you could double up in the wet zone by knitting with 2 strands or adding a doubler.
Otherwise, maybe find a peace fleece coop? Or some on the TP. It's a great, sturdy wool. If I were making pants for my almost 3 year old, they'd be peace fleece b/c it could hold up to his wear and tear and heavy wetting.
Targhee is pretty great, too. Super soft, not cheap though. I think there is some undyed at the mosaic moon yarn store on hyenacart, but haven't checked lately. Dashingdachs.com should have some soon, too.