Check tint shops. The guy who tinted my windows had a whole 100 ft roll in his shop. It looked just like the oem matte black stripes. He said the roll was around $50.
Check with Automorphosis (think thats how you spell it). They did my 09 SS Matte stripes and they do custom cuts if you like... The GT500 part will not be an issue, OEM quality
oem stripes are sold in individual pieces, which is good for someone who just needs a small piece to replace, but added together it is a fortune, plus paying someone to do the who set on correctly
Interesting thread, one of the reason I wanted to purchase a stripe delete was so I could get the Super Snake strips down the road or do two different color Shelby strips.
I did stripes in my 08 when it was new and damn was that expensive! It took a while to get all if the pieces in since they are all different part numbers. The Ghost appearance package I orders was charcoal stripes that you can see in the daylight but looks like a delete car at night.