This project is definitely under way, one crane is up and the other is going up. I will try to get some pictures and add them when I get a chance. From the NY Times (behind the subscription wall for some reason):
"A bright yellow crane has recently gone to work, the most solid sign yet that the reconstruction of the Uffizi Gallery here may really, finally, actually happen."
The article goes on to quote some Florentines about the difficulties of doing anything new here in Florence, noting that the archive space that was emptied nearly 30 years ago to make room for this expansion is still empty. THIRTY YEARS AGO! You gotta love Italy...