(My apologies, it's a bit late for coherent writing, but I wanted to finish this before time gets away from me.)
So, back to modesty. What is it really all about? I think it's about avoiding pride. If we look at it this way, the admonition to be be modest in our dress has more to do with dressing so as not to intentionally draw undue attention to ourselves, being "free from conceit or vanity." Wearing a swimsuit to church would be immodest, because it would serve to draw attention to myself. Going swimming in tuxedo would likely have the same result. It seems that it is all about our attitude in the clothing choices we make. The outcome we desire has an impact on the correctness of an action.