Just north of Brighton, England, is a firm named Tanks4Hire that rents Russian/American/British tanks and armored vehicles for film and promotional work. They have over 1300 acres to film in, which would enormously lower the costs inherent in these vehicles (like shipping a 30 ton Sherman). They do have one tank that doesn't weigh more than your average sedan, a replica MK. IV British WW1 tank. It's made of marine plywood on a steel chassis with a diesel engine. Full size modeled on one of Bovington Tank Museum's Mk. IVs, it looks good and won't crush your driveway. Sorry, but they don't rent out vehicles for proms.
Tanks4Hire Mk. IV in action.