The 7 sounds interesting.
Now I have fundamental doubts about the possibility to really tap into the potential of 24MP in an APS sensor without a tripod. I am still also not sure about the value of having a very compact body with large lenses.
In other words, are either the A77 or more compact mirrorless cameras from other brands not better options considering the actual usage and expected shooting goals?
You shouldn't have doubts Bernard regarding a greater need of a tripod. The cropped format has never had a disadvantage regarding shutter speed, compared with a full frame of the same pixel count. In fact, it probably has an advantage.
The 1/FL rule still applies as long as the focal length is FF 35mm equivalent. In other words, if a 1/75th sec exposure with the D3X using a 75mm lens is sufficient to produce a sharp image, then a 1/75th with the Nex-7 using a 50mm lens will should produce the same degree of sharpness as it relates to camera movement.
Sharpness of lenses is another issue, and here the larger format can have a clear advantage at shallow DoFs that require the use of wide apertures.
For example, the sort of shallow DoF one would get using F4 on a 75mm lens with the D3X, would require using F2.5 with a 50mm lens on the Nex-7. In these circumstances, it's very likely that the 50mm lens at F2.5 will not be as sharp. Even if it were as sharp, the D3X would still have the advantage because its pixel spacing is wider.
However, at long DoFs, this sharpness advantage of the full frame camera tends to disappear. For example, most lenses would be sharper at F5.6 than at F9, and sharper at F10 than at F16.
As regards camera shake without use of a tripod, the cropped format has the advantage when one equalises DoF because the wider aperture at the same ISO allows for a faster shutter speed.
On the other hand, one can sometimes trade in the shutter-speed advantage of the cropped format to counteract the noise advantage of the larger format, by lowering ISO one stop, or more, on the cropped format.
Have I missed anything?