Originally Answered: What can the maid of honor wear? She's not so manly to wear a tux, but not so girly to wear a dress or skirt!
That's a tough situation! Since she's the maid of honor, she can certainly wear something different from the rest of the bridesmaids. What I did for my wedding was to allow the gals to choose thier own clothes. The bridesmaids had to agree on one thing (which the maid of homor also happened to choose). It was my wedding, so I had veto power.
There are some femenine tuxedo style pants available for women. She could wear those with a nice satin blouse and heels. That could actually look very attractive. Anything cut for a man would look frumpy on a woman, but there are slim-cut dressy trousers available for women.
I agree with you that it's not right to force her to wear something she hates. I guess you have to decide whether her friendship is more important to you than her attire. She also may want to consider whether or not being the MoH is an honor that justifies a little compromise.
In the end, although many brides may not agree, a wedding is not really all about you. It is the celebration of two families joining together as one, with the support of their loved ones. It will be over in a flash, and you will probably only look at the pictures occasionally. The marriage, not the party, is what is truly important. If you feel that she is a good friend who will support you as you journey through life with your spouse, she deserves to be the MoH, even if she shows up in a potato sack. That being said, a little respect for your wishes and less drama on her part wouldn't hurt, either. Crying over clothing seems a bit much to me.
Were I in your situation, I would go to a store like Nordstrom with her and seek out the help of a personal shopper. They are professionals. Image is what they sell. You give them the parameters (i.e: no dresses, formal please, feminine, under X number of dollars, here are the wedding colors) and you would be amazed with what they will come up with.
The fact that she is gay does not mean that she can't wear something made for a woman. She is a woman, after all. It would be different if she was transgendered. Then, I suppose she would be you Man of Honor (nothing wrong with that). Since she identifies as a woman, she can certainly wear women's clothing for the occasion. If she hates heels, the ballet flat suggstion is a good one. She can wear those with women's tux pants. If the pants are long enough, she could wear "mannish" shoes and no one would notice. She could even wear women's tux pants with a regular tuxedo shirt (preferrably tailored for a woman) with a tie that matched the groomsmen. I still think that a satin tuxedo shirt would look nicer on a woman, but that's just me.
I have to respectfully disagree with the other posters who stated that "This is your day, so do what you want." Having been married for about decade, and having born 2 children with my husband, I think they are wrong. The wedding may take primary importance in your mind right now. It certainly did to me when I was a bride. However, in the years to come, what memories do you want to take from the experience? It sounds to me like your MoH is a dear friend who will be around for the rest of your life. In light of her orientation, her crying does not seem nearly so dramatic. Still perhaps a bit over the top, but more understandable. If she is a more masculine person, and she matters to you, you may want to keep that in mind.
Even if she says she is OK with standing on the sidelines so that you can have nice pictures, do you want to do that? Keep your priorities straight. If she has serious moral problems with dressing in a girly manner, and you love her, that needs to be considered.
When my best friend got married, I was 9 months pregnant. I remember telling her of my pregnancy and letting her know that I was OK with her nixing me from the ceremony. After all, in the lovely (truly) navy chiffon dresses we'd all be wearing, I'd look like a huge blueberry. Very distracting. I was married about a year before she was. I recalled reading on some of the bridal websites questions from brides-to-be who wanted to kick pregnant friends out of their wedding. I thought that was rather shallow, but I kept that self-centered, Bridezilla attitude in mind when I spoke with her. We all get a bit self-involved when we are brides. That's not so bad, considering the fact that if you have children, self-involvement is pretty much out the window for the next 20+ years. She was horrified that I felt the need to mention that option! She decided to go with a custom bridesmaid dress provider, who altered an enormous floor length dress in the same color (but a different style) for me. She did that because I was her friend, and it was important to her that I stand for her wedding. I cannot tell you how much that meant to me! She is the Godmother of my children. I love her like a sister.
You sound like you are truly interested in having your best friend be comfortable and involved in your wedding. Please, please, please do not allow outside influences to compromise that attitude. Repeat to yourself: She is more important to me than a freaking dress.
Again, check out a personal shopper (with your BFF) at a department store. Seriously. I think you may come up with an option that has everyone smiling.
Worst case scenario, she'll wear the same tux as the groomsmen. Would that be so horrible? Really? How hurt would she be if you eliminated her from the ceremony because of a wordrobe issue?