By "mtb shorts" do you mean baggies?
If that is the case, I'd love to hear also if anyone has found a pair of good, workable, women's baggies. Most of the women's baggies are cut to look like cutesie "surfer-girl shorts". Cute off the bike...but boy do they suck on technical downhills!
I stick with lycra off-road, no problems with catching the shorts on the saddle and if I want the longer leg-length I can just buy a small men's size.