I was totally excited when I saw the SD15 was coming out and the specs. I have to say that after the release, I am not that excited. My major hurdle is the price.
The sensor kicks butt, and while it is a 15MP camera with about 22-28MP performance in output, I can pick up the D3X from Nikon with 24MP, have better build, better DR, 14bit color, more features, better ISO performance and a larger selection of lenses and accessories....all for about $1,000 less.
If the Sigma was price between $2,000 - $3,000, I could see value in it, but they priced it in lower end medium format territory. For me that is the stratosphere. Even at the $7,000 expected street price, it has priced itself out of my radar.
It is a VERY nice camera, just not sure Sigmas marketing team was really understanding the market they are facing.
I have to say though, looking at the colors you got from your test shots, they really are georgous files.