Well, the thought that gave me this idea was... *drumroll* Gackt! He looks scary like Cloud in his Vanilla video, though admittedly a good bit of it is his hair and contacts. But hey! He's even got a motorcycle. Also, Gackt is an actor; he has a movie called Moon Child. I promise. It's hard to get a good quality, but here's a picture and a link to a video:
Vanilla VideoMy other idea: In the role of Cidolfus Demen Bunansa, I cast... *drumroll* Jeremy Irons! Eh, no reasoning other than looks.

Okay, idea three: She's a little old, but I always thought of Quistis as being older than she actually was anyway... *drumroll* Diane Kruger! Besides looks, I thought her attitude in National Treasure kind of fits... Here's a picture:

And now to break my own rule (I can do that 'cause I posted three actual ideas), as Riku... *drumroll* This guy. Nyah. It's an awesome cosplay.