I am 5'11" myself, so I feel your pain! I was told that there weren't many places that sell them; the only one I can remember is Gap Maternity (you can look and shop online) and it's not in all of their clothes. A lot of their pants/jeans are over $50, but they have really good sales!
I also lucked out at Kohl's...none of the stuff I found was officially a tall size- but I got a couple pairs of pants there that were still long enough after I washed them!
Personally, I am opting for dresses and skirts cause it will be summer for the larger part of my pregnancy. I thought I would be more comfortable.

)
ddeessaall:
Does anyone have any idea where I might be able to find maternity pants/jeans for those of us that are 5'11" and taller?? It's hard enough to find them in regular sizes so I'm wondering if I'll have to spend the majority of my pregnancy in dress, skirts and shorts.
Any ideas??