I've just completed this photoshop above. The small sporty roadster category is seriously lacking. The MX-5 Miata is about all that's available in a small RWD convertible for under $30K. Everything else is either too big, too heavy, too expensive, or on the wrong FWD platform. In keeping with Kia/Hyundai's philosophy of getting more for not a lot of money, I think they should jump into the roadster business and offer something that looks great, is RWD, fun to drive, and price it at around $30K. Give it about 220hp but keep the weight down to about 2800lbs or no more then 3000lbs and I think they have a winnder.
Kia isn't even new to to roadster business. They used to rebrand and sell the Lotus Elan back in the 90's as a Kia. Too bad the engine in that car was crippled and the handling wasn't as fun as the original Lotus, but at least they gave it a shot. If they decided to jump in with a full fledged attempt, it could be worthy competition for the likes of Mazda.