I don't see why not.
The reason why you're not seeing them right now is that the car manufacturers that require low SAPS oils in their engines also require the HT/HS viscosity to be pretty high (3.5 cP or above), and I don't know of any 0w-20 oil that could have HT/HS viscosity this high.
There may be some specs out there that call for low SAPS and low HT/HS, but nothing comes to mind at the moment...