Moleskin isn't just for trousers. Shirts, weskits, caps - you could dress like a mole all over if you liked. A much friendlier fabric than denim, but it never seesm to have the same vogue. Maybe the name worries people.
Real moleskin has been used for gloves and weskits, by professional molecatchers. But you'd need an awful lot of moles for a pair of trousers.