For a while, I was able to shoot up at Arlington a bit.  Our location there in the afternoons is close to the ramp used by Airlift Northwest.  They have some Airbus Helicopters EC135s that they use for aeromedical flights.  It is a nice looking airframe and theirs are painted well.  (They have recently painted one in UW colors which I have only shot from a distance.). They seemed to be in action a lot while I was there so was able to get the teams crewing up, departing, arriving and shutting everything down.  They are happy to give you a wave too which is nice.