I just had to post here and brag. Oh yeah, this was a lot of work and took me four solid days, and boy am I proud of it! :^)
I started by drafting a pattern from a pair of jeans that I love... and which are falling apart. I didn't cut them or take them apart, I just pinned the part I was measuring to some old cream-colored twill fabric I had in my stash (and I pinned through it to the measuring board). I traced the finished sewn shape. When I cut it out of my jean fabric I eyeballed it and cut between 1/4 and 1/2 an inch more fabric to each side of the pattern piece.
And then I tried as hard as I could to mimic the construction of the original pair of jeans. It was pretty neat actually. Most of the seams that have double stitching are folded together so that the cut edges are completely enclosed inside the seam. One side is ironed to the wrong side and the other is ironed to the right side, and they're dovetailed together. This seam is fun to make.
I got it to fit pretty closely to the old pair, although it was a bit roomy. Luckily I waited until after sewing to wash it for the first time and it shrank to an almost perfect fit. The waistband is still a bit on the loose side, but it's not too bad since the hips fit really well. (Oh, and I was the idiot who was too lazy to put that last little detail on mine - belt loops. And of course I could have used them).
The only thing I was really unhappy with were the front pockets. They needed to be deeper, and sewn into the fly better. Oh well, I guess they're just for sticking my hands in since they're too shallow for anything else.
Back Pocket Detail
Incidentally, that is the only belly picture I was willing to post because I look like I have a serious beer gut in the side view pictures! My husband needs to hurry up and procure a DDR pad. :^)