Don't have an Evo, but I've been looking at them extensively specifically for their size and trying them on for "fitting" in anticipation of picking up a Droid X.
It doesn't seem big at all to me, I can palm it and conceal it in one hand, IMO the perfect size requirement. Everything else is just tiny and still recovering from the "zomg it has to be the size of a piece of gum and fit on a key chain" fasion craze. I think small is out, we've proven we can make things smaller than our human ability to interface and interact with it.
The only thing I won't be able to do is keep it in my front pocket in a car with side bolstered seats, but no big deal since you'd likely want a landscape car dock for a phone like that anyway (not to mention you'd be crazy to not take advantage of throwing it in a charger any chance you get).