... I was thinking Precocious Apprentice, Metamagic School Focus, Midnight Metamagic, and Spell Focus (Illusion) would work (with Heighten Spell being your bonus metamagic feat). I don't think you can stack metamagic onto a spell with Metamagic School Focus like that. Would require nongnome adaptation, and two flaws.
(What, incidentally, would be the most fun 2nd-level shadow spell to heighten to 4th level and cast once a day at first level?)