i think that would look awesome. i saw a car with the same setup and it looked gorgeous.
edit: here i found these on my computer, i know it is not a coupe or a 1968 but it has the colors and rims on it. i do not know anybody who would find that combination tacky.
I think you've chosen one of the classic Mustang paint schemes and it looks great. I was this close (Zookeeper holds up two closely-spaced fingers) to painting my car blue with white stripes. But with about 95% of the Mustangs in my area some shade of blue, I went with blue stripes and white paint. Be careful to really think your stripes through as was previously mentioned. Stripes don't look the same on every car, and width is a huge factor. Also it's a good idea to stick with the Shelby-sized stripes (can I say that without risking copyright infringement?) since they were tapered and straight 10-inch stripes don't look right.
I've got a picture (one of my favorites actually) of a 66 coupe that's a metallic blue with white stripes and it looks amazing. I'll try to post it when I get off work.