Jack88:
I have an HI blade that was blued by a previous owner, and it came out great. I don't know what method he used. Here are a couple of pictures. The blade, made by Sher Kami, is a Hanshee model, 18.5" overall length, 23 oz. It was made for the late Danny Fletcher (DannyInJapan on Bladeforums). Danny was a martial artist. He had the butt end of the handle narrowed a bit to accommodate his fighting style.
View attachment 722049 View attachment 722048
In a later post, talking about sheaths, you say you'd like "something that I wouldn't be afraid to take in the salt water with me." Sheath or no sheath, bluing or no bluing, I wouldn't want to go near salt water with an HI blade (this probably applies to any blade made in Nepal). The kamis use 5160 high carbon steel, which is great for most purposes, but rusts very easily. The handles would also be vulnerable.
You could mitigate that with frequent use of mineral oil, but if you're going to dive, swim or wade, I suggest that you do that with a different knife, and save your khukuri for everything else.