This is pretty awesome idea.
Easier than a spool, or a lincoln locker... Price is gotta be cheap though, spools are ~150 - 200 bucks. You're target audience is the guy who wants a locked rear end and is a cheap bastard (like me). If you can figure out how to make one for a Toyota drop out, you'll make a mint.
I'd leave the material in the backside of the lock (where the nuts are) to support the side teeth, looks like it could break the teeth out.
Couldn't tell by the pics, but those should be lock nuts or at least loc tited. You don't want those nuts backing off.
P.S. - I would not have shown the pics on a public site like this, if it takes off, there are several shark type vendors who will steal this idea. Especially if you don't already have a patent.
P.S.S. - Change the stupid name... Chock Locker or something a little better.