Samurai amphijeep are British made kits sold for about $20k, or you can buy these cars complete as Dutton Commanders.   Said to be “convincing”  in water and on land (to 85 mph). Doner car was the Suzuki Samurai with important innovations to typical amphibians including the prevention of “axle suck”.  For sale at Motoreum on HWY 620 near Anderson Mill. See their link at right of this page.