ugly as hell! good luck attracting new generation buyers.
toomanycanons: I can see the niche buyer carrying this along with other cameras. Suddenly the right scene comes up, he whips out this camera and gets the shot. Puts it back in his pocket. Quicker than changing lenses.
The Sigma is a snail when compared to others so It would be tough to just whip it out and get the shot right away unless you are taking pics of flowers :). For people shots, forget it.
spidermoon: A good camera with those big lenses is like a Ferrari with hummer tyres ;)
Likewise, a small high quality lens and a small sensor is like a Ferrari with a 2 cylinder hybrid engine.