Thanks for your advice! I agree that putting some money forward a decent shotgun mic and some lights would be a good purchase, something I'm going to do as well.
In terms of the canon t3i and the t4i, would the video quality not essentially be the same as I'm getting on my Sony A58? Does the ability to use magic lantern on the Canons produce a much better video output? And how would you compare the t31 or t4i with magic lantern to one of the panasonics mentioned above?