After a short discussion on IRC with some other developers the conclusion was
that byobu isn't worth shipping with Grml for the time being. So marking this
issue with "won't fix" for now. If someone wants to see any special features in
Grml's screenrc or tmux.conf please report them to us.

byobu 5.0 isn't available within Debian yet (see http://bugs.debian.org/cgi-
bin/bugreport.cgi?bug=653387). I'd love to see byobu 5.0 in Debian/testing and it would 
be awesome if someone would be working on it to get it into Grml (so we maybe could have 
a decent profile for Grml's tmux/screen setup?).

Any volunteers?

regards,
-mika-

it started as a fancy screenrc file, but is now a very nice and actively
developed own project

since the GNU screen project is practically dead since a couple of years, the
byobu backend will be switched to tmux in the next version (but is still
supported by byobu) 

http://blog.dustinkirkland.com/2011/12/byobu-5-released.html

give it a try