It's not such a crazy idea. When I did the research for the Cornwall AA back in 1986 I found out that the then market-leaders in Germany were rarely transporting patients. Their advantage was that their crew always included a trauma trained doctor and they were hospital based. The doc would invariably have a road ambulance on hand so he cold fix-up the patient and send him/her on their way back to the GH or specialist centre. If you can start an AA operation with a standard fit helicopter delivering the doc and his kit plus maybe a paramedic, it's a much cheaper option and can give you some good data to enable the case to be made for a full HEMS machine.
If we are talking UK then it is essential to work with the local Ambulance Service and receiving hospitals. Attempts were made in those very early days to short-cut the system in Devon, London (and incidentally in Saudi Arabia). For any HEMS system to succeed it must be embraced by the entire health care system.
G.