The Lexus GS is set to get a comprehensive redesign sometime next year, including thoroughly upgraded underpinnings that will for the basis of Lexus’ next generation 5 Series fighter. Like the current GS platform, the new architecture will form the basis of the next IS, which in its current form is essentially a shortened and squished GS.

With that in mind, the next generation IS will follow shortly thereafter – likely sometime in 2012 – and in addition to the current sedan and convertible, Lexus could finally add an IS coupe to its lineup. Lexus recognizes that it hasn’t had a credible player in that market for far too long, and with the new Mercedes-Benz C-Class coupe around the corner and the two-door BMW 3 Series holding its own, the obvious question is why hasn’t Lexus done it sooner?

According to our sources, it was easier for Toyota to make a business case for the IS cabrio, particularly given the SC430’s imminent demise and Lexus’ need for a drop-top offering to fill the hole. If the coupe does come to fruition – and we’ve been told in no uncertain terms that it’s in the cards – expect the two-door IS to bow sometime in late 2012 or early 2013. And it’s safe to assume an F version will arrive with in year of the coupe’s debut.