In reply to john.

Here's a functional demo.

Not perfect but I think it works pretty well based on some rough testing.

Activate it in a site in a WP network and it should give you a drop down list of the sites you have admin rights to. You can clone that post to the blog you choose.

With some more effort, I'll have it go to the destination site etc. but I figured I'd see if this was close before doing too much more.