Arri introduced three prototypes with prices ranging from E 50 000 to E 130 000. They all share a new CMOS 3.5K sensor with 800+ ISO rating and 12+ dynamic range, plus 1-60FPS.
Estimated delivery date 6/2010 for the cheaper model, 12/2010 for the most expensive. The less pricier models will feature an LCOS evf and 16:9 aspect ratio. The most expensive a optical viewfinder and 4:3 aspect ratio (for anamorphic shooting).
The D21 owners can upgrade to the ultimate model.
All will have on board HD recording and the two more expensive uncompressed ARRIRAW recording. At the moment there are three certified Arriraw recorders from S.two, Codex and Keisuko Giken.
The camera downscales the captured pixels from 2880X1620 to 1920X1080 for HD and from 3072X1728 to 2048X1152 for 2K In the high end model the camera utilizes the full 3392X2200 pixel count.
I saw an D21 with ans S2 flash recorder very similar to the Panavision one.
There was a demonstration of the new sensor, with a small revolving car model encompassed in a small box lighted from a color changing source, that was quite impressive at least for its low light capabilities. Also a working prototype of the new EVF.



In order to achieve wider exposure latitude they incorporate some kind of HDR method by combining two differently exposed readouts from each pixel.

The two entry models are physically almost the same The second has more connections for peripherals (essentially a different side panel).The basic one can be upgraded to the latter. The more advanced with the optical viewfinder block is bigger and the entry models cannot be upgraded to the top of the line one.

The two entry level ones with the EVF will exhibit rolling shutter but minimal because Arri will increase the read out speed of the panels. More details weren't available (either not finalized or not yet ready for public).
The top of the line as is the case with the D21 doesn't have the problem because the shutter of the optical viewfinder, blocks the light in between readouts. (I'm not sure if it is believable).

All three will have onboard HD acquisition and the ability to record Raw with external device.
The person wasn't allowed to discuss if the SDI is HD or 3Gbs neither the nature of the HD recording (probably not finalized yet).
Owners of the D20/21 can upgrade to the top of the line model when its available, ahead of first time buyers.

Some thoughts:
The basic model is aiming against Red Epic and with a price to match (around $5OK). The middle model is factory ready for follow focus and peripherals, for those who can pay upfront the difference, but essentially identical. The top of the line at $130K is considerably cheaper than the F35.
In the brochure they have a test against a competing camera (didn't mention Sony but it is obvious) and the new Arri outperformed the competing camera in Low light, dynamic range, noise.

Someone recognised the other camera at IBC as a F35 - I gather they weren't supposed to see it during the demo, but the other camera's handle gave it away as the Sony.