I can't see them dropping the Boxster. Boxster sales are tough at the current pricing. Cayman sales
appear to be good at 4-5k more than the Boxster but there's still a lot of deal making going on about the cost at least they seem to get discounted pretty heavily locally putting them right on par with the Boxster. It's actually pretty hard to find the Boxster you want it seems, just aren't alot around compared to the Caymans. If they drop the Boxster for a Cayman cabriolet they'd basically be adding 10k to the cost of a car that looks and behaves exactly like the current Boxster. All they'd really have to do is put a Cayman badge on the back of the 987 Boxster. I don't think it would sell without steep discounts but what do I know. I think they've positioned their model line-up really well right now from a pricing perspective. Boxsters seem to be selling pretty close to msrp with Caymans slightly below so the grumbling about the ragtop costing more than the hardtop probably doesn't reflect pricing reality. The Boxster name carries a very well known and a real asset as well. I think they would take a long hard look at dropping such a well recognized name. They Cayman's a great car but it will take time for the name to roll of the tongue of Porsche lexicon. Their focus is on the Panamera right now I think which fills another great niche. Nice talk about their plans here.
http://www.motortrend.com/future/future_vehicles/112_0607_porsche_911_gt3_panamera/index.html