I love the co-ed friend showers - DH has a lot of friends whose wives wanted to be invited/they wanted to get us gifts, but I feel bad because the husbands/boyfriends are the links - I feel guilty inviting people I don't know well.
As for the out of towners? My MIL invited 25 people that live out of town or out of state. I now feel like that was really gift grabby and I know they probably won't be able to make it but she didn't want anyone to "feel excluded if a local family member brought it up" We pretty muchy sent invites to all the wives from our wedding invitation list (she didn't even know some of their first or last names)!
I wish I would have put my foot down & said no then send a birth announcement to all of these people instead. I'd rather have a smaller shower with people that I actually KNOW there...