Finally, I spent almost half year to compare different options and decided to buy a new digital camera from my favourite band, Canon, Powershot Pro 1 two weeks ago.
Here are some of the canon official links
http://consumer.usa.canon.com/ir/controller?act=ModelDetailAct&fcategoryid=144&modelid=9823
http://www.canon.co.jp/Imaging/pspro1/index-e.html