Good job on this fork of statpress. This seems like a very flexible implementation.
A minor issue which I believe has been carried across from the original Statpress and seems to occur in most of the many forks of Statpress - with the possible exception of StatpressCN (if I recall correctly) is that when selecting one of the Statpress Visitor pages, such as visitor spy, the menu indicates that it is still on the original statpress page (shaded background & notch on left side), so the current class is not being applied to the actual current menu item.
Another minor issue is that the main menu title 'Statpress Visitors' wraps onto a second line making the menu looks a little untidy as the WordPress admin CSS appears best with single line admin menu titles. The first child menu item is also called 'Statpress Visitors', so would it be better to rename the main menu item to Statpress (or something else shorter such as Statpress V?) to keep it on a single line?