as T'Ryssa Chen
Liza plays "Ivy" (Topher's sidekick) on Dollhouse
(and has played the much more serious Agent Lee on NCIS
), so I think she has the right blend of youthfulness and maturity to play Tryss (considering that Tryss, despite her behaviour, is old enough to be an officer).
Hmm, I see what you're going for. Doesn't work for me, but she's more in the ballpark than most of the suggestions I've heard.
Of course, most people would probably say Lucy Liu with pointed ears. In my imagination she looks like Ezri with longer hair. Are you keeping it to yourself, Chris, or did you have a particular actress in mind? Perhaps Maggie Q?