I cannot find a option for setting the minibar to a vertical position, it is not listed in styles but is listed in help. I downloaded the minibar editor but do not understand how to use it and it does not contain any additional styles.
There is no Vertical MiniBar template in the default installation, however, you can make your own using the MiniBar Designer. I think Randall or some other user made a vertical style once. Hopefully they read this and make it available for everyone. Otherwise, I can make a vertical template up for the next public release and include it in the installation.
The MiniBar editor is an advanced tool that requires some thought on use. To use the editor, you load in an existing toolbar template or create one from scratch. If you are not familiar with editing utilities such as UI editors then it may be difficult. But I suggest, go ahead and have a go. Don't overwrite your original minibar templates and you should be okay.