Alright. Got some ideas for rp's. So I thought I might as well list em here and see if anyone bites.
1. Life switch.
Basic idea. We play two (or more) characters, one in a higher position than the other which they use to mess with the other and then the lower position decides to get back at them somehow and basically switch places with them. Whether this be through magic or through tricks. This could be something like two siblings, royalty and a commoner, Babysitter and babysat, ect.
2. Nursery machine.
Classic concept. One person (or multiple people) somehow gets stuck dealing with some kind of machine that is convinced they're babies and will stop at nothing to make sure they're taken care of as such, regardless of how said babies feel.
3. Sequence of unfortunate events
Have a bunch of incredibly unlucky stuff happens to our character(s) that causes them to be dressed up. Like say they happen to be mistaken for commiting a crime and have to go on the run, only to end up in a doll factory or something like that.
Here's and artist with a bunch of good examples on this subject if you don't fully understand:
http://dayeandknight.deviantart.com/gallery/