Erlang has heart (http://www.erlang.org/doc/man/heart.html) for similar reasons. Of course, it also has distribution, for when the whole computer it's running on dies.
I use runit (http://smarden.org/runit/) instead of daemontools (same sort of thing, but a bit less opinionated about e.g. where it gets installed). Rather than expecting every daemon to implement its own supervisor, logging system, etc. correctly, just use one of those.
Does daemontools care anymore? I use "supervise ~/.dotfiles/service | readproctitle ............." to start my user-local services when I log in. Works like a charm.
It's been a while since I installed daemontools. IIRC it created a bunch of root directories (e.g. /commands). There was also an OpenBSD port for runit already.
I use runit (http://smarden.org/runit/) instead of daemontools (same sort of thing, but a bit less opinionated about e.g. where it gets installed). Rather than expecting every daemon to implement its own supervisor, logging system, etc. correctly, just use one of those.