R290 (propane) and R744 (CO2) heating/cooling in the United States? – GreenBuildingAdvisor

I’ve been holding out for an air-to-water heat pump that can handle heating in cold climates, cooling in the summer, has low global warming potential, and the ability in heating mode to produce water that is actually hot, so that it could be used for domestic hot water or perhaps even to replace a boiler on old fashioned radiators. 

My understanding is that R290 (propane) and R744 (CO2) refrigerants can both do all of these things, and LG has a model (and perhaps other companies?) available in Europe, but not in the United States, due to regulatory restrictions (propane is flammable and CO2 requires high pressure).

Does anyone know if any product like this exists in the US? Or when products like this will be allowed in the US?