@b0rk Very nice article, (I haven't quite finished yet).
I wanted to point out that ctrl-U is NOT delete the whole line for readline (long ago I had expected it to be that and got surprised).
It is:
unix-line-discard (C-u)
Kill backward from point to the beginning of the line.
The killed text is saved on the kill-ring.

Which you will ONLY discover if you use it after having moved your cursor to the middle (or front) of the line. In which case you'll need to followup w/ ctrl-K