I'm here, actually trying to get some work done so I can only reply briefly.

I can relate to all you're saying, my wife is now becoming more receptive that yours appears to be.

My concern is her respect for you, I know my wife HATES FAT, so I made a huge effort 2 years ago to loose 20 kgs, for my health and to please her.
We have an obligation to do so. But she has a Biblical obligation to respect you also.

Maybe the way she sees you needs to be discussed.
Maybe you could work on loosing wieght - if that is an issue for her.

My wife once suffered from anorexia before we met, in her mind wieght is still an issue.

On the kilt side of the matter:

Be patient, even in Biblical understanding, we are all at differing places. Loving kilts is something of a personal revelation not dissimilar to spiritual revelation.
She is not at the same place of understanding that you are.

be consistant, when she sees you are serious about kilts, happier, more comfortable and that (hopefully) your friends and those around you give you compliments.....that may sway her mind a bit.

Try to interest and involve her in celtic events, movies, buy her a pleated kilt-skirt if she wants one.
(if it interests you also) involve her in celtic music, outings, maybe take up Scottish Country Dancing (we did), and other places where other men will also be in kilts.

Must dash, hope it works out for you brother!