You'd probably need to catch, skin and cure around 150 moles for a decent pair of trousers and that's if you could find someone to sew them all together.
I've got a pair of faux moleskin trousers, or did have as I've not seen them for a few years, but they are incredibly heavy and warm to wear and are ideal for any activity that allows you to stand still. ie marshalling at a Fell Race!