Atshen

So I can go do this mission tonight and spam the boards with "I am teh ubrz r3gin scrapper and I soloed the Infernal mission!!!" tomorrow morning.

Cool.

Seems to me the most logical way to implement shape shifting is as part of your costumes. Just allow you to select your body type and size in the costume shop when you alter your costume. That way when you changed costumes, your shape would be changed as well. This would mean you could only shape shift once you had a second costume, or possibly like capes, only after completing some task, and only into available body styles and sizes. Of course that is pure speculation.