Re: Bring a post in from another blog
There are a few options:
1) Featured Posts MU – https://wordpress.org/extend/plugins/featured-post-mu/ – uses a template tag that you can add to your homepage template or a widget.
2) BP Sitewide Featured Posts – http://dev.benoitgreant.be/blog/2009/11/buddypress-sitewide-featured-posts/ – uses a widget, but you could setup a widgetized frontpage and then you can use this widget. You could probably also modify the code to use it as a template tag.
I misread your post, Wayne.
If you want the post’s content from another blog to reside on your main blog, you should think about making the user a contributor on your main blog. Then you won’t run into this issue.