I've just dug out a pair of US military Goretex trousers I was given ages ago. Far superior to the Brit ones - double fabric on the ass, double on the knee area and two press-stud flaps on the front for pocket access / ventilation.. They would make a great pair of cut-offs if you can get hold of them. I'll be chopping these down soon enough.
So where do you get 'em from then ?
I got mine from a member of the USAF!
I dunno - Google perhaps? It seems to have most things!
[url= http://www.surplusandadventure.com/shop/army-surplus/clothing/u-s-army-clothing/genuine-issue-us-military-gore-540698.html ]These[/url] if your skinny... ๐
I sorted these out last night and, teaching myself as I went, hemmed them on the sewing machine! I am a domestic god!
I was pleased to keep some of the zip for ventilation and put the velcro tabs back on. They come to about 3" below my knee when legs are bent, so down to anyone else's ankles!

