There's been some discussion of (the lack of) high-back PUL pants and I've been searching around. I still haven't found any, but fetware sells a high-back version of their ultraflex polyurethane pants http://http://www.fetware.com/ultraf...ants-p-31.html.
These don't have the cloth laminate so they're neither as comfortable nor as discrete as PUL and they are not machine washable. They're a lot more comfortable to me than vinyl, though, and they're supposed to last a lot longer. They don't crinkle as much as vinyl. (If I'm going to be indiscrete, I'd rather indulge in it.) Or, I should say they crinkle differently---sort of, but not quite, like a plastic bag. I find them a little creepy, but I wear a onesie over them anyway, so it's not particularly noticable.
And they are truly effective in containing my (massive) night diaper combination.
Best compromise I've found so far.