Hey, for anyone stuck with Yosen Zeros with awful 510s, the Orchid V3s will work on them and sit flush. So will anything with a fully (or almost) threaded 510 base. It's still not ideal, but at least they aren't absolutely useless.
I'm going to start a DNA 40 transplant in my "best" one over the holiday, weld & re-tap the horrible one when I get a chance.
ETA: The internals are very cleanly installed on the V2s, it should be a piece of cake to drop the DNA 40 in as far as I can tell. Looks like I can use their button board as well.
Also, looking at all the similar mods that use the same dimension steel body, I'm thinking that it starts out as a section of square stainless tubing. It would be pretty easy to make your own custom one if you have access to a machine shop.
Look at this one & you can see what I'm talking about. It's even slimmer than the Zero, looks just about perfect size in the hand. (Also watch that guys silent tutorials on the Origen Genesis V2, he's really thorough & ends up with some impressive builds.)