Hello, ffmedic42
I must conclude from your post that you don't own or wear a kilt at the present time...and thats ok. There's nothing shabby whatsoever about a tuxedo. I don't recall ever seeing a standard tux worn with a tartan sash. That doesn't mean that it hasn't been done. If you find yourself a bit self concious about renting and wearing a kilt & jacket, perhaps you might consider tartan trews instead.
I might suggest posting the question on the Hector Russell forum.
http://www.talkaboutkilts.com/cgi-bi...be38fe11e1ffff
I don't post there, but from what I've read there, they bend over backwards to get the right definitive correct answer for you.
Just a word or two about kilts. The humble kilt and jacket will put just about any tuxedo to shame. IMHO, leave the sash for the ladies and get a kilt. There isn't a kilted man among us who hasn't been apprehensive about shedding trousers and wearing the real McCoy. I can tell you that most men that try it are hooked. I can also tell you that the ladies go bonkers for guys in kilts. I'm 50 plus and balding and even I get winks and nods from younger women. My advice,...give the kilt a try.