With a quick search, one of the vehicles featured is available:
Military Vehicle Solutions has a number of CVR(T) Sultan for sale. These Command Vehicles can be purchased as refurbished (RESET) vehicles or as a restoration project for private vehicle owners. Parts and supplies can be bought through or sister company cvrtpro.com
militaryvehiclesolutions.com
The main gun of a tank is classified as a destructive device under US law, and technically you should be able to buy it with a 500 dollar tax stamp, but they will just refuse to issue the tax stamp in order to bypass constitutional law.