Can Custom controllers be horizontal? Are they only vertical. Also can I put them on different sides of the window: Left, Top, Right and Bottum?
Nope. Not at this point in time.
If my memory serves me right there was a nice example showing how to use a tabless tabpanel as a navigation type custom controller that could be placed anywhere. It may have been at:
Yes, DO use a tabless tabpanel.
I use them horizontally all the time.