How to customize live Ubuntu CD?
How I can make a custom Ubuntu Live CD ISO that have Dropbox app installed in it?
If somebody can make this ISO and put it somewhere for downloading, it would be great!
It would not be legally distributable if you did make it. You could only legally use it for personal use, and I don't see a good reason to do it. Dropbox downloads and installs about 50M of proprietary and pre-built binary pieces into your home directory, and runs from there. And synchronizing all your files into the live ramdisk probably isn't a great idea either. It seems like it would be better to just grab the one or two files you might need to play with on a live CD, from the web site while running in the live CD.