What's interesting to me is that Marina Sirtis was originally cast as Tasha and Denise Crosby originally cast as Troi, but their roles were swapped. I'd love to have seen that version of TNG.
I don't know of anything else she's been in that she's played it tough, but I doubt they would have cast her that way if they didn't initially seen something of that in her. She certainly has the presence for the role if her outgoing personality at conventions is any indication.