Here is a possible solution to this dilema. Either have a clean look and risk a ticket or be safe with bulky lighting.
I made this quick review on Custom Dynamics LED plate frame and Integrated tail light. Not quite 9" but unless you're being reckless I doubt you'll get pulled over for just that. Besides, they are very bright an make you more noticeable at night with a clean lay-down look on the fender.

 

this is the same setup I've just installed on my 06 FXD.

 

It's the way to go. Clean and bright!