> So what's the best to do right now to get something like this into
Emacs?
Elementary. Get people to experiment with the respective codes.
Peter's packages are quite small and can be included right away -
provided he has signed papers. His code is far superior to that of
flyspell.el.
If people want to experiment with my code they'll get all the support
they want. It's stand-alone and you can, for example, speck a buffer
with Aspell and have ispell check words with Ispell at the same time
(with different languages). You currently can't run flyspell and ispell
with different executables or languages simultaneously.
> (Does ispell-multi use timers or post-command-hook?)
It won't care. When run with flyspell it obviously uses the
post-command-hook.