Thanks for the tag, @Adina al'Mari . This is a very interesting thread. As a non-binary person leaning very towards the masculine, I think that short VC coat was gorgeous. But it's not exactly easy to make..
I personally find sashes sort of silly, and have been wondering what other options for Ajah representation there are. I really like the tie idea. Think it would also work with a cravat, if you want to be more fancy/costume-y.
I think it would be really cool if someone (such as Badali) made enamel pins that were the flame of Tar Valon but in Ajah colors, similar to the necklaces that Badali used to have. You can put those anywhere, really, and they're not gendered. The drawback is that it's not really a project that most individuals could complete themselves.
I love the long coat because it is both gender neutral and easier to adapt to different body shapes and sizes. For many people it would be harder to get a good "fit" with the short coat - it is not as forgiving a style for most body types as the long coat.
I love the pins idea... great thing to wear when donning full garb is either inappropriate or not possible. One possible alternative to enamel pins that an individual could make themselves would be beaded Flames / Fangs fastened to either a long pin or clutch type pin back. I'll have to do some experimentation.