http://crews.tv/blog/2011/03/22/sony-fs-100-enters/
It is yet a rumour at this stage but it is very likely to be true and official announcement will come very soon.
Well, as it was previously observed, the E-mount is actually 135 full frame compatible!
The most important thing is that Sony now has a new 35mm "Super" CMOS sensor, which is specifically designed for Full HD video recording. And straight-forwardly, it should be able to take high quality still photos at the same time.
The good news and new hope to all those old Pentax K-mount users is that the new Sony FF sensor could possibly be used by Pentax in a coming Pentax FF model, but only if Pentax could get it and more so provided that Pentax is willing to make one!
Update (3-24): I have been mistaken, the "Super 35mm" is not 135 Full Frame format!
See the Sony brochure and we can see:-
http://www.sony.co.uk/res/attachment/file/59/1237480643259.pdf
I must have been dreaming for a Pentax FF for too loooong so that I could not see more about the facts! :-o ;-> Too bad.. :-(
Related:-
Old Question: Will there be a Pentax Full Frame DSLR?
Two Major Meanings of Full Frame
Compatibility of DA Lenses on Full Frame