Via Amateur Photographer.

These two cameras’ specs had already been rumoured for some time, but now they seem to be official. Sony is going to introduce to new DSLRs with a radically new concept (which is technically neither new nor radical, but new and radical for both DSLRs and Sony).

The new models, called α33 and α55 (official designations: SLT A33 and SLT A55, where SLT = “Single Lens Translucent”), no longer feature the classical, moving SLR mirror, but rather a translucent, fixed mirror, through which both imaging sensor and AF sensor are simultaneously provided with information. This means Sony were able to 1) introduce HD video featuring phase-detection AF (instead of the more conventional contast-detection AF) and 2) introduce continuous shooting rates of up to 10 frames per second, due to the fact that the mirror does no longer need to be moved during single captures.

A minor drawback of this new design is that due to the translucent mirror, there is no more optical viewfinder (contrary to the design of the Canon EOS RT), but instead a high-resolution electronic viewfinder. On the bright side (literally), an EVF will provide not only a consitently bright image – independent of what lens you are using -, but can also show additional information like gridlines, a live histogram etc., which is all not possible in traditional DSLRs.

The new α33 and α55 seem to be the first of a new generation of hybrid DSLRs, combining the best features of both DSLRs as well as mirrorless system cameras.

While there are no full review available as of yet, The Luminous Landscape have already gotten hold of an α55 + lenses, and have just published a first field report on the camera.
Revision: DPReview seem to have had and α55 for quite some time already, as they have just published their in-depth review. Wow, you guys were pretty fast this time!
Revision 2: Imaging Resource also have a review up already!
UPDATE: PhotographyBLOG has a hands-on report with body images from all angles!
UPDATE 2: The Phoblographer also has a hans-on report, featuring pictures taken with the α55 and the new Zeiss Distagon T* 2/24 ZA!