It may be a shot in the dark, but could it be like the unmarked Boeing 737's that fly to/from Area 51 from LAS and be an unmarked Governmental aircraft to ferry workers to and fro? Maybe not, as I believe those 737's are white with a red stripe running along the fuselage at the window level and don't carry any markings at all.
A conspiracy theory maybe :
I've checked Jetphoto's as well, and no joy there either. Maybe my theory has some mileage, though the dome on the top looks like some form of radar and the colour scheme to me smacks of Navy, but I'm no officionado on U.S. military or Government colour schemes.
P.S. I am not a pinko commie subversive.
