So . . . . I'm thinking that I've inadvertently finished your bounty for you . . . .
What else do you need? I'd be happy to add anything (that makes sense to me as being productive ;-) Or, if you wish to join the project, I'd be happy to add you . . . .
Finally someone cared to browserify that. But the bounty is about a native implementation without node. 600kB is absolute overload.