I would consider the short writeup about Dropbox posted on the SANS Forensic blog to be a great success. There was considerable feedback, as well as a number of folks commenting on twitter. I'm glad there was interest and that it was found to be useful; mission accomplished there.
For anyone interested in the full article, it is now on Forensic Focus. Many thanks to Jamie Morris for providing hosting - not just for my research, but for all the others out there as well.
Hope you enjoy it, let me know what you think.