fuzzy-hair-man wrote:While your at it you may as well make the top half as well, ie most cavers if they go to the extent of making or buying specialist caving clothes use overalls or coveralls generally out of cordura, nylon, or PVC (if you are going to get really wet and cold) or some other suitably tough fabric.
Here in T.A.G. country a lot of cavers use just cordura pants or cordura shorts. I once bought a full cave suit and found I only used it a few times. I always overheated and found I usually had the top pushed down and the sleeves tied around my waist.
Regarding a pattern. . . you are probably going to have to modify any standard patterns. My caving pants also have extra fabric at the knees which is fit in using a few "tucks" to add extra fullness at the knees. This extra fullness keeps them from pulling when climbing or crawling.
Perhaps just making the pants a size larger than you usually wear might solve the problem. The other thing you might consider is adding a "gusset" if some areas seem too restrictive.
My pants are also re-inforced in the seat area. I tend to be a "butt" caver when going down breakdown slopes.