As far as I know the only thing shared between the Busse companies is how to make the knives. I haven't seen any patterns shared between the different companies, and the steel sure isn't (most of the time). All the Scrapyard knives are pretty much originals as far as I can tell.
Whether or not they make a knife without a choil is just a design choice. Given the number of models that have been made without, which is... the Tank Buster is just about the first I've seen (and I jumped on it). I definitely think we could use some more, especially on the smaller blades (the Scrapper 4 has how much edge?).