here's a quick tip about how you can change the hostname on your MacOSX and keep it changed after a reboot:

Of course you have to type that as root.

It seems there is also possible to set in it /etc/hostconfig but that file on it's own will not work. You have to load it in netinfo somehow but I don't know how to do that.

I think I like the /etc/hostconfig approach more then the scutil (even if it has to be loaded in netinfo ) because it's somehow closer to how most unix/linux systems do it.
Anyone knows how this can be done ?