Presently, there is only one dominant, automated method for running daemons/services on a computer with Gentoo Linux installed. This is using the start-stop-daemon script. In the spirit of Gentoo's freedom to choose approach, and in following with the recent addition of choice of EDITOR, I believe that the choice should be left up to the user. Other methods of running services could include the ability to use inetd, xinetd, or tcpserver processes. Daemons/services could also be run under svscan/supervise from Daniel Bernstein's daemontools package. Daemontools setups, in particular, interest me. I, myself, would be willing to add on to many of the present ebuilds for some of the more popular daemons.
as you point out, this has to be handled on a pkg by pkg basis ... basically what it comes down to is the person making the ebuild figures the best way of running the app (often times suggested by the install process of the app itself) ... if you'd like to make more scripts and such please feel free to open more bugs about specific packages
