Meta Stack Overflow is not, actually, a meta site in the api sense.  It tracks reputation, and has a distinct set of user accounts from Stack Overflow.

Image hashing isn't really compelling, as you'd have to be polling `/sites` quite frequently to make use of it, which you shouldn't do.  Rather, just pull the image down once a day or so.

Clarifying the relationship between meta<->parent is already [status-planned].