There are currently three manufactures making single engine truboprops (Piper - Meridian, Socata - TBM, and Pilatus - PC-12). Two companies have announced they are are considering making a single engine Turboprop (Cessna, Cirrus) and two others are actually making single engine Turboprops ( Kestrel - Alan Klapmeirer, Epic - Experimental and has plans to manufacture a part 23 ). Sounds like a crowded market.
King Air is just a trade name and will not make one make a bit of difference.
If you you look at the three existing manufacturers, the Pilatus is a Truck (a nice one) but might be overkill for most applications, the TBM is very fast (310kts) but way over priced, and the Meridian is the most efficient and a great value for the money. Most the the the wannabes are trying to build a plane that combines the qualities of these three. If I were to speculate the only two that have a chance at that are Kestrel (as a result of the carbon fiber airframe and Honeywell engine), or Cessna because of there deep experience and resources.
