It shouldn't be hard, at least in terms of turning the LED on and off. (I have to admit I never learned morse code myself, so I probably don't know all the tricks involved; I know a bit about how letters and numbers are keyed, but I think there's something more intricate involved when keying out full words and sentences...)

In any case, hooking up keyboard keys to sets of LED pulses shouldn't be too hard. I guess you could also feed text files into the thing and get series of pulses out...

It'd probably be easier to work with this using the "torch" mechanism rather than the "flash" mechanism, as I'd have finer control over "torch" timing; would you need the highest-level brightness for your morse code flashes?