Looking at the init file it might make sense to use systemd unit instances [1].
But it's still a small wrapper needed to convert the env files to ucarp params.

[1] http://0pointer.de/blog/projects/instances.html

Interesting.  I'll have look at that.

Done.  Test if you like, works for me.  Thanks for the pointer.  I basically used the initscript as the bones of the wrapper, since the daemon doesn't take a config as an argument.  Once configured, things like systemctl start ucarp work.