ORIGINAL: awc
I'm in the same boat, the stripes seem to be way too wide in the back. I was always a fan of the stripe options you could choose on that "Paint your Challenger" web application that has been floating around. The 'Hemi' stripe in particular always caught my eye.
Rider Graphix patterned the new stripes off of a 1971 Challenger T/A. Those stripes were wide, too. See:
http://www.allpar.com/model/challenger.html