As far as I've seen, the only way to get the ghost badge for CoV is to bring them to the ghost traps in Fot Hades. No one else has come across a ghost mission as a substitute.
There are a few. Check out Hermod's Guide to Unlockable Contacts...that's got a great list.
Hope this helps!
Story Arcs:
"The Joy of States-mas", #533168
"A Mosaic of Shattered Dreams", #497506 (2011 Players Choice winner!)
"Television Presents: Attack of the Toons!", #373710
"Lightning in a Bottle", #376222
Is there any other "missions" like this in the game where you have to kill a certain number of critters (ghosts) and then you get to talk to someone?