Seriously, you can buy one right now.
It's not the first time this has been thought of. Henry Ford had the same idea to utilize industrial hemp for the production of car parts, specifically body panels. Ford actually tried this in 1941 but nothing came of it, but this didn't stop designer and retired Hewlett-Packard employee Bruce Dietzen from trying again and succeeding. The result is the (first two gens) Mazda Miata-based Canna 100 and 130, the Canna Turbo 265, and the Canna EV. Each variant has a body that's made of pure hemp. The fibers are woven and hardened with resin and then painted.
And, with the obvious exception of the Canna EV, the cars are gas-powered and can even run on ethanol. If hemp ethanol ever goes on sale, that'll work too. The base 100 and 130 models weigh about 2,200 lbs and produce 100 hp and 130 hp, respectively. The Canna Turbo 265 has – you guessed it – 265 hp and tips the scales at 2,400 lbs. That, according to its official specs, is a weight ratio comparable to the Porsche 911 Cabrio. The Denver Post recently reported that Dietzen drove one of his cars from his home state of Florida to Denver, Colorado in the hopes of attracting investors. Starting price? $42,000. And no, Dietzen doesn't smoke dope; he only drives it.