If you want something that has a skirt or shorts bottom, I highly suggest It Figures! brand swimwear. They sell them on QVC's website, and you can get them on eBay as well sometimes for cheaper.
The thing I like about them, is that they have flattering suits in BOTH regular and plus sizes. A lot of designers don't realize that even women who are a size 8 or 10 sometimes have cellulite, or a large bust, or saddlebags and are not comfortable with it all hanging out.
It Figures has suits for thigh/hip coverage, and they also have suits to camoflauge the tummy/waist area, or a large bust. You just browse through the specific figure flaw type you are trying to cover up. Some of their skirted suits are really, really cute.
Another thing I really like about them, is that the skirt and short bottoms are a little LONGER than what they would be, say, if you went to Wal-Mart. Some of the skirted suits there are only as long as the panty underneath...so you aren't covering much.
Check them out...I love them. Even when I am thinner, I don't like to show my upper thighs too much-I have some stretch marks on them from my babies.