The 645D is officially back on the road map, and it will be compatible with the old 645 lenses!
Here is the official press release from Pentax Japan:
March 24 PENTAX to Exhibit Reference Products at Photo Imaging Expo 2009 in Japan
HOYA CORPORATION PENTAX Imaging Systems Division is pleased to announce the exhibition of the following reference products, all currently under development, at Photo Imaging Expo 2009. This is one of the largest annual photographic merchandize trade shows in Asia, and will be held this year from March 26 to 29 at Tokyo Big Sight in Ariake, Tokyo.
Reference Products - Product type: Lens-interchangeable medium-format digital SLR camera
Model name (tentative): PENTAX 645 Digital
Product information:- Extra-large, super-high-megapixel CCD image sensor with more than 30.0 total megapixels (tentative)
- Compatibility with existing smc PENTAX 645 interchangeable lenses
- Market launch scheduled for 2010
- Product type: Interchangeable standard lens for exclusive use with PENTAX medium-format digital SLR camera
Model name (tentative): smc PENTAX-D FA645 55mm F2.8
Product information:- A standard lens designed for exclusive use with the PENTAX 645 Digital (tentative name)
- Advanced optical design with all properties of lens element groups, including curvature and lens coating, optimized for digital photography
- Market launch scheduled for 2010 (Will be marketed simultaneously with the PENTAX 645 Digital camera body)
Notes: Model names, designs, specifications and market launch schedules of these products are all tentative and subject to change without notices. Prices of these products will be announced at a later date.