I've just started making this new theme and most of it is together the way I want it, but there's still some little problems. This is what the side bar looks like overall:
http://img.photobucket.com/albums/v109/mindtweak/litestep/bar_open.jpg
This only opens when you move the mouse within 2 pixels of the edge of the screen with a hotspot. It disappears when the mouse exits a hotspot that is the width of the bar.

The section with the time is a xlabel. the arrows popup the theme menu. the quicklaunch buttons are made with xpopup from a shortcuts folder. the tasks with xtaskbar. and the systray at the bottom with xtray.

One problem is that the popup quicklaunch menu disappears as soon as you open the popuptheme:
http://img.photobucket.com/albums/v109/mindtweak/litestep/menu1.jpg
and then the whole bar disappears once you move 40 pixels away from the left edge:
http://img.photobucket.com/albums/v109/mindtweak/litestep/menu2.jpg

I want the whole bar to disappear a once when a selection is made from the menu. Also, I want the whole bar to disappear if you pick something from the quicklaunch menu.

I'm not sure if this is possible, but can I make the hover displays for the taskbar the same as a popup menu entry?
http://img.photobucket.com/albums/v109/mindtweak/litestep/task1.jpg

And finally, I can't get the systray to have a fully transparent background when there is a window underneath. As can be seen in the first picture at the bottom.

I'm not sure that you can have 2 xpopups open at the same time - maybe you can if they are pinned (I haven't tried).

Make a bang that hides all the modules which make up the bar, and look for events to call that bang. I can't be more specific than that I'm afraid.

Yep, you can have multiple xpopup's open, as long as they're pinned. An unpinned menu ought to vanish once it loses focus, and only one can have focus at a time, so...