Thank you. I have that site added on my favorites on my laptop. From what I've seen it's all stainless finish. But maybe I'll contact them.
Yes sir, they have Stainless and Black oxidized listed. However, they do offer anodized washers to add some color. So, they "might" be able to get you what your looking for. I'm not sure, just trying to provide another possible avenue.
BTW, those bolts you provided the link too look really good. Should look really nice with your powder coated items.