Is there any way to invite a mod to a PM conversation?

I can't seem to figure out how to do so, if it's even possible... and at this point I'd rather like to. 

Send a PM to a mod...

Yep, in an existing PM you can add extra recipients just above the reply box at the bottom of the PM, in the same box as where the names of the existing recipients are shown. The "PM all mods" link in the Forum FAQ is the quickest way to get a response, however. 
 

Thanks a lot!