Dude, are you my long-lost twin brother? I am also 5'5" with a 31" waist and I often despair of finding pants. Convertibles are the worst because they are so hard to hem because they generally have a zipper in the low leg( to facilitate getting in and out of them without removing your shoes I guess).

The good news is that I finally found some that work great. The 28" inseam Sahara pants from REI fit me like a glove. I notice they are on sale again so I may get some more.

http://www.rei.com/product/746905