unusual request...but perfectly legal.
Lets be very practical about this. Yes you can have a private ownership of a sherman tank in the US. Theres a whole slew of problems geting one registered an all, and de-armed so it will pass the BAFT, but provide you have the resources, yes you can own a tank.
Now for the tricky part...where can I buy one...?
Contact the people who make war films in hollywood. When they needed special props for films and such, they used contacts in yugoslavia, spain, rommania, and such to supply them with military hardware from WWII. One country that comes to mind is Israel, although they may not want to part with something that helped save the country over and over. But if you truly are serious, and have the resources to do it..contact the film companys to see if they still have the information on countries that currently have WW II vehicles in their inventories.
You may think im joking..but im dead serious.
Have you considerd salvage? there are approximetly 120 shermans at the bottom of the sea...right off the coast of france...still in fairly good condition. Yes, im talking about the D-day Landing sites...there are some areas that are not protected as the war memorial sites, and salvage at 100-200 feet depth is not as complicate today as it was in 1944.
There are also numerous shipments in ships around the british Isles, and quite a few off the coast of the US when the blitz was on from the U-boats.
Your best bets for obtaining one is from the film industry. Go for it, and let us know how you do.
:tank: