Here is an image in reference to the bottom of the SnowSpeeder and the big box under Luke's SS when it takes off in the hanger:

http://img141.imagevenue.com/img.php?image=98565_sw5_1_122_226lo.jpg (SS in upper left corner)

(the box would have to be digitally erased and the hanger in the background recreated if this shot is to be altered)

But something else I never thought of before: in a lot of TIE fighter shots from behind you never really see the red engine lights on their ION engines. Here is an example:

http://img137.imagevenue.com/img.php?image=98589_sw5_6_122_701lo.jpg#