Some of these I could not obtain an image file, just a link. I imagine you've seen some of them.
Here's a Demon with a modified 340 stipe. I'd say its a successful example of using the stripe line without doing something that does not belong on a Demon.
http://www.moparmusclemagazine.com/..._1009_1971_dodge_demon_modified/photo_10.html
This is a subtle mod to the 340 stripe with door handles in black.
http://www.moparmusclemagazine.com/featuredvehicles/a_body/1971_plymouth_duster/photo_03.html
Very nice stripe mod on the green Duster.