The big question has got to be 'Is it worth it?' Police or HEMS units would have to make some compromises that would affect their core operations. Should they stick to those core op's and leave the winching to SAR or would the public be receiving a better service if we were all winch equipped?
It's a question to your goverment or your officials! Situation isn't the same in every country. We have countries in Europe with "specialised" HEMS and Police Units and we have Police units doing the cop job
and the ambulance or HEMS missions.
In the most european countries it seems to me that the cops today and especially in the future will do the special "law and order" jobs. The most of the new delivered ships are special equipped with FLIR, NVG, lasersystems, radios, link and transmitting systems and so on. They could be used for HEMS jobs but the ships are heavy (the new german border guard EC 135 have more than 17km wire inside for all possible equipment) and it needs time to remove the specials. That makes no sense in a country good covered with civil HEMS operators and army SAR units.
Compromises could be possible but with compromises you can't get the absolutely best results.
Rumour going on the short haul should be described in JAR-OPS 4 as HHEC (Helicopter Human External Cargo).