Yeah there's two buttons on the back in a rocker configuration that are usually used for volume.

I see what you mean about the "keyboard interface", actually the interface that some people thought of is an "enter your initials" arcade-style thing for typing in search strings, but it'd be a little unwieldy. The strategy I outlined actually works pretty well for me, and is a LOT less buttonpresses than would be needed for an on-screen display like you're talking about.

I could probably whip up some kind of arcade initials style input application in an hour or two, but I have too many other programming chores I have started and never finished.