Most sedans are built to be people-haulers first and speedsters second. There are quite a few sedans that can hold their own on the track, but very few of these can be considered supercars.Fortunately for speed fiends, there are a small handful of conceptual and production sedans out there that are built to go fast. If you have ever wondered what a four-door Ferrari sedan would look like, or if you just want to see a four-door convertible that can push 200mph, continue reading below.Netherlands automaker Savage Rivale can be thanked for the awesomeness that is the Roadyacht GTS. The Roadyacht GTS has four doors, is convertible and can top out at 205mph.All of this speed comes courtesy of a lightweight build, with a total weight of 2,820lbs, and a big 6.2-liter V-8.The automotive world may be clamoring for a Lamborghini SUV, but a super-powered sedan from the Raging Bull is far more likely to see the light of day. That sedan would more than likely be the Estoque, the company's stunning four-door concept.The winds are blowing towards production for the Estoque, but nothing official has been announced as of yet.The Bugatti Galibier will be the end all be all supercar sedan whenever it goes from concept to reality. Bugatti execs have ordered the original Galibier concept delayed until 2015 in order to tweak its design.Not much is known about the Galibier, but what we do know is that it will have 850hp and price tag of around $1.5 million.