There is still no word on the release of the Sigma SD1 DSLR. The camera was initially set to launch around February/March of 2011 (source: Sigma @ Facebook):
Hopefully this will not turn into another, almost 2 years delay, like the SD15.
The Sigma SD1 will have a 46 MP(4,800×3,200×3 layers) 24×16mm APS-C X3 sensor and dual TRUE (Three-layer Responsive Ultimate Engine) II image processing engine. There were some rumors that Sigma is working on a full-frame version of that sensor. The SD1 will not have video, but they may consider it in future models. More info on the SD1 camera can be found here and here.