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No, not really. There's "the playhouse coop" for which you can buy plans from isthmushandyman. There are also "playhouse coops" made, literally, from playhouses or by adapting playhouse plans. 
The idea behind isthmushandyman's coop plans is that it ends up looking sort of like a kids' playhouse so is less likely to attract the ire of anti-chicken neighbors.  It incorporates a fully-covered run with a small "roost box" under a single roof so the whole thing forms one structure.
Cuteness or architectural stealth is often the idea behind converting a "real" playhouse to a coop, but another reason is that they make very nice coops with few modifications and can sometimes be bought for less than the materials to build your own would cost you. Although they don't look it on first glance, they're much larger than the 4 foot wide, 2 foot deep, 3 1/2 foot tall roost box of the isthmushandyman coop. They will usually require a run to be attached to or built around the coop.
I haven't had the bravery to go through our receipts to see how much our coop (modified from isthmushandyman's plans) cost. We used 2x3 lumber instead of ripping cedar deck boards, used corrugated plastic roofing instead of metal, changed the outside wall of the roost box so it swings down for thorough cleaning from outside the run, and made an external nest box on a side of the roost box. It took 3 weekends. I'm not much of a builder at all, but nobody lost any fingers. I'm certain we spent a few hundred bucks on materials. I also "needed" to buy a new jigsaw to cut out holes for the window and the nest box. We already had a circular saw and a drill/driver (and hammers, straightedges, levels, etc.)