I've been watching this, and I have a few more suggestions, and a few questions.
First, I'd love to see a lefty clip option on this. Button locks are more or less ambidextrous by nature, easily actuated by thumb or index/middle finger. If the clip is recessed there should be a filler tab, though, so people don't whine.
Second, I think I can explain the flipper orientation a bit better with what I suggested earlier. G&G Hawk do a lot of flippers with a bottom rounded front flipper (parallel to the edge) instead of top mounted. As far as I'm aware, the top mounted flipper is specifically because of laws in South Africa that ban a bottom mounted flipper, like traditional flipper tabs or front mounted ones that disappear into scales when open. A button lock doesn't get in the way of a bottom mounted flipper like a liner or frame lock does, so it's really nice to bring something different to the market.
Third, what steel were you looking at doing? There's a lot of high performance cheap steels out there, from stuff like AEB-L to BD1N (if you can find it, I looked and couldn't), if you don't want to go with super steels.
Lastly, I know it's going to sound silly, but you are going to use hardened Torx or hex fasteners, right? Philips and flat heads are a little cheaper, but they are so prone to stripping.