I was shocked and delighted to find that, after pairing a Bluetooth keyboard to my iPhone, the default emacs-lite Cocoa keybindings work there too. C-a to beginning of line, C-e to end, etc.
Being able to quickly type text via a real keyboard is quite neat (except for C-Spc switching the input method, turns out I hit that quite a lot), but having to get back to the phone in order to cut/copy/paste is quite frustrating.