I have been wanting a fashion harness for quite a while, however, I couldn't justify buying one when I could easily make a custom sized one. I really like how the harness looks with my bra, but I'm not sure I'm sold on how it looks over clothes. If I do wear it over clothes to go out, I'll probably add a wide elastic belt under my bust; I'm hoping that will make it look less like a boob hoist. Please excuse the blurriness of some of the photos.
The harness only cost me about $4 to make. The neck hole is a bit too tight, so, I plan to alter it to make it adjustable. If you attempt to make your own harness, I highly recommend making the "waistband" and neck bands adjustable; it is tricky to get them tight enough that they don't slouch, while not getting them so tight that they dig in. I bought the elastic off eBay and it was stretchier than I would have liked, so, it flops around a bit; I recommend using a firmer elastic if you make one yourself. If I make another harness, I would like to experiment with different sizes of elastic (or maybe fake leather), and larger d-rings.
My harness design was inspired by this bra that I saw on Vintage Vandalizm's blog: