Most any reasonable volume 12 volt
air compressor should do. Good ones can be had at off road 4x4 shops, as they like a good compressor when out in the boonies.
Harbor Freight has a fair size one too, just not sure about the quality over time.
You may want an extra check valve on any compressor as a leak could bring water or water vapor back into the compressor itself, which would not be good.
That said, I am with Steve H on a demand pump as a more practical solution, and it gives an increased water capacity, as there is no need for an initial air space in the tank.