Very first try at this ... whaddya think?

Most of my observations have already been taken, but one I didn't see anyone mention of was the darker color over the word "Plymouth" isn't even over the "Pl" portions of the sign. I like symmetry and if that was done it would look a little better.

As far as price goes. I'm not overly versed at what it would cost to powder coat that sign in the first place, but would expect maybe a 20-30% higher premium than what a single color would cost. If you could charge that much more and make a profit while justifying the amount of labor and materials utilized I believe you'd make more than trying to get 200% or more than what a single color would cost.