How can I get messages beta to start in "hidden mode"
You can create an AppleScript to do that for you.


Open AppleScript Editor
Type/paste this in:




    tell application "iChat"
        set minimized of window 1 to true
    end tell




launch "iChat"
tell application "iChat"
    close window 1
end tell



Save as an application somewhere
Open System Preferences > User/Accounts > Login Items
Click Add, navigate to application, add and enable