There is an interesting read over at Legal Match about what requirements need to be met for a TSA patdown to be considered inappropriate. Granted the information is outdated based on the new patdowns as to the specifics (for example, some stations no longer use hand held wands), but in general it pretty much comes down to this:

When Does a Pat-Down Become Inappropriate?

A pat-down becomes inappropriate whenever the TSA's guidelines are not followed.

I'm not saying it's right and I'm not saying it's wrong, but if they are following their guidelines, and you consent to the search as they outline each step and allow them to do so, I think there's little chance of a suit working out in your favor. They won't let you through if you don't consent, which is another issue, but they do give you the option to opt out of it all.