typewriter scrolling-ish shortcut

I love typewriter scrolling, but I wish sometimes that I had a keyboard shortcut that would redraw the screen with the current line at the top of the window (like Emacs does with the (Recenter 0) command).

Does anyone know if it’s possible to extend Cocoa text editing apps to do this? I’m posting here because I figured that the methods might be similar to those that Scrivener uses for typewriter scrolling.