It’s rather trivial that you can use the same profile between Windows and Linux by finding the profiles.ini for one or both platforms and editing it so that the profile folder is the same. It’s a bit more difficult with Lightning though as this extension has separate versions for different platforms. So if you have Windows version installed, it looks odd in Linux and vice versa.
At this point, don’t give up! Go to http://lligabirres.com/francesc/00_index/05_net/05.02_EMAIL_CLIENTS/05.02.02_THUNDERBIRD.html and scroll down. Simple instructions that I just followed and it is looking fine from Windows. Haven’t tried from Kubuntu yet, but should be ok, I hope. Not to mention that the profile itself is on ext filesystem so I also installed Ext2IFS which you can get here: http://www.fs-driver.org/download.html.