So - you can only run muplugins_loaded from a MU Plugin, plugins_loaded from MU or Plugin ( not theme ) and after_theme_setup from theme and all of the above, does that sound right to anybody?

there is a chart for that :) rarst.net/wordpress/wordpress-core-load

:D Oh hey, I've seen that chart! That's too bad, I need a hook between muplugins_loaded and plugins_loaded