They are catching up! :S
http://www.dpreview.com/news/0609/06093007seitzd3.asp
http://www.dpreview.com/news/0609/seitz6x17.jpg
http://www.dpreview.com/news/0609/seitzroundshot.jpg
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Already there with the 39mp single shot backs and exceeded with the Betterlight backs....
They are real pricey.. :)