Patent offices make a habit of (purportedly) leaking application drawings of striking new cars. This week it’s the new SLS AMG roadster.The SLS AMG, Mercedes-Benz’s first in-house supercar in ages, will add classic roadster style to the range by 2012 if these leaked sketches handed in by Merc at the European patent office are anything to go by. Although similar to the fixed-roof SLS in terms of proportion the roadster will differ quite radically with regards to its construction. Those characteristic Gullwing doors are replaced by conventional front-hinged items on the roadster and it sports a traditional fabric roof instead of a folding hardtop. The SLS AMG roadster will cue a similar suite of engineering features to its fixed roof sibling. This means you’ll find an extremely vocal 425kW 6.2l V8 up front, a carbon-fibre driveshaft fed transaxle DCT transmission running through to the rear and all-wheel double-wishbone suspension. Expect the first SLS AMG roadsters to roll off the production line late next year.