Hi Joe, I have a 1/48 scale M1A1 I bought online from a place called War Tanks.com a few years ago. Don't know if they are still around. Mine is made of resin and is 6 1/8 inches long (tank body only) and 2 3/4 inches wide. I will take some pics when I charge up my camera. I have mine on either an Atlas or Weaver U.S Army 53 foot flat car. The tank is not quite as wide as the flat car.
The ones you are looking at look pretty good.