Sgian Dubh
I can't say about dirks, save for the fact that they are way too expensive. I can get an infantry sword made in 1853 for the price of a modern-produced dirk. Heck, my Baskethilt made circa 1760 costs less than some dirks made in the 1800's!
As to Sgian Dubh, have you tried Scottish Lion? They sell some with wilkinson blades on them which are pretty good. They are pricey, as one would expect, but pretty good none-the-less.
Which reminds me of a time when I got kicked out of the Beau Rivage casino in Biloxi, Mississippi. The Beau is a swanky affair and my wife and I went to go see stomp. I wore my kilt, brogues, a Prince Charlie vest and tie, and, of course, my sgian dubh in the sock. Now, my dress SD is metal but for show. When I'm at games, I have a good stag-horn that I wear. Well, one thing led to another and I was told weapons were not allowed in the casino by a snarly woman in a green jacket. I asked about pocket knives, and she said they were not weapons. I explained, first, that the blade was no longer than my Uncle Henry that I keep on my key chain, and considerably less sharp, and that, as a matter of law, the Sgian Dubh, where defined by any law in the world, is legally NOT a weapon and can be worn into parliament. I also pointed out I could do an equal amount of damage with my Pilot pen in my sporran. She pointed out that I would have to leave the Beau Rivage, sgian dubh under cover, and never return.
Fine by me.
Ash