I've got a pair of the Montane Pro pants - they are made from a heavier weight, stretchy lycra material with a harder wearing fabric over the backside and the knees. Very comfortable, good fit and summer wear for up on the hill, but probably too warm for indoor exercise IME. I'm not sure of the durability of the fabric as there's some surface pilling already - thankfully I didn't pay full price.
There are some baggier-fit running tights about - I've got some Asics ones that I picked up in their outlet shop a few years ago. But if you're only wearing them in the house, who's looking?
I agree on Ron Hills - best left in the 1990s, cheap, crackly polyester only good for making your hair stand on end...