I attempted to calculate, from pics posted everywhere, the size of the die:
Where TBredB was 11.33 by 7.47, I estimate the Barton core to be about 13 mm, with the same height. (using the various reference points around the CPU). The picture is skewed, so a pixel by pixel comparison wouldn't be accurate.
The wattage is estimated at:
68.3 for the 2500+, same (?) for 2800+, 74.3 for the 3000+ and unknown for a 3200+.
Here's a comparison pic, the source of my "guesstimate" (along with AMD specs).