The wagon wasn't 1 year only, it was built in Mexico for years and was just certified for the US and Canada. It was like that for about 4 years so the current one will probably stay like that for another 2 years at least. Plus, the wagons always lag the sedans so if the sedan is all new next year the minimum the wagon will arive is 2 years.
I strongly doubt there will be a VW diesel hybrid in the next 2 years or soon. Diesel is great for highway, hybrid is great for short trips. Combine them and you've got a really fuel efficient, complex, heavy, and expensive car that will require high fuel prices to sell well. They probably built the VW Golf TDI hybrid as a concept car and will make a gasoline hybrid. Don't forget the 1.4L turbo and supercharged Euro engine that would probably be a better replacement for the 2.5L gas engine now.
I also strongly doubt the wagon will change for the next 2 years. As Joe said, it was only new to the US for 2009, it's been around for years. And the 2011 Jetta sedan would come first followed by the wagon later. The A5 VW Jetta sedan came in model year 2005.5 but the wagon didn't get here until model year 2009. I suspect they will work on the NMS (next/new midsize sedan) Passat replacement before the VW A6 Jetta wagon.
I do believe that the TDI engine will still be available in a 2011 VW Jetta TDI but I haven't read any confirmation that it will be for 2011 or 2012 or if the engine will change much.
It's definitely going to be all new for 2011. It's probably going to be a bigger overhaul than the Golf. VW has clearly stated that they are trying to reduce the cost fo their cars so the base Jetta will probably lose a lot of features. The TDI will probably be a midline model and hopefully they have optional xenons like the Golf, finally.
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