"mbit" will win 

Sure, if bitcoin becomes popular and pricey enough, I hope some incarnation of 'mbit', 'mBTC', 'millie' or whatever gets used.

USD seems to be more popular the Bitcoin, but that isn't a valid reason to use it.
That's a different thing. I just mean: if everybody uses "USD", I wouldn't use "DXUS" or something like that to describe dollars.
Anyway, I am not trying to be obnoxious, just want to streamline/standardize things.