Here is an interesting project from Øystein Bech "DreymaR" Gadmar.
I mainly adopted the "Extended" Layout, which gives you extended functionality through replacing capslock with a mod_level_5.
The good thing is, you can add this to your existing layout with an option in dconf-editor.
The layout looks like this in his file:
I had to adjust it a bit for my needs, because some functions didn't work as expected.
I had to disable the media key functionality on the function row, because I couldn't change to my ttys.
Futhermore, reenabling capslock lays on scroll lock, but I didn't like that. I changed it with dconf-editor to activate when I tap both Shift keys a time.
(See page 4 in the forum post I mentioned above, There I've described my steps to solve these problems).
Have fun!