New York Times:
http://www.nytimes.com/2009/03/23/us/23crash.html
Re-states fatalities as "14 to 17" (all on board), notes that THIS particular aircraft may have been configured for 12 seats (although not clear if that includes cockpit or just the px seating)
"It was unclear if that many people, including children, could be safely accommodated on the plane...."
"The aircraft was described by F.A.A. officials as a Pilatus PC-12 that was registered to Eagle Cap Leasing of Enterprise, Ore., and was apparently rented from that business."
128CM,EAGLE CAP LEASING INC Oregon registration record
N128CM?
FlightAware > Live Flight Tracker > N128CM
Looks like decision to divert to KBTM took place over Challis, ID - about 100nm out.
Aircraft N128CM Photo by Mike Khansa
Here's a PC-12/45 listed as seating 12 (NOT the crash aircraft)
Pilatus PC-12/45 - N167AR - Aircraft For Sale