Try Duluth Trading...there are stores, but online is great. They have many styles of t-shirts and their shirts are longer than others.

Here is a link to a style that might work for you:
https://www.duluthtrading.com/women...ngtail-t-shirts

This particular style is nice because it is flattering and can be dressed up (i.e. it doesn't look like "just a t-shirt").

Good luck in your search!