I agree that the captain's jacket and other extra outfit pieces would be great. I liked Picard's captain's vest in "First Contact" as well. Or the away team jackets from the movies. How about the original turtlenecks from "The Cage" and the first few shows of TOS?
Ah. I apologize for jumping to conclusions. The rainbows blinded me to the logical conclusion, which I do agree with.
Perhaps this option will be more fair: Make two open jackets; one split to just below the sternum with no undershirt of any kind, another fully open with the grey Captain's shirt beneath.
A far cry from chest hair customizability options (which considering how many times I had to suffer Picard's manly chest would to 100% canon), but it offers options for both sides that show off enough chest to be enticing while at the same time having a stylish, more modest option available.