I am trying to make a theme with a vertical taskbar and I can't figure out for the life of me how to do it. It appears that Taskbar3.dll has no such functionality...is there a taskbar module that allows such a thing to be created? I'd have to imagine there would be one, but in my searching, I haven't been able to find one.

how vertical do you want it to be?
In Darkbar by Teschio there is a task bar down the right hand side of the desktop... I think it uses tasks-0.92b from looking at the theme.rc, but I could be wrong because I'm very new to all this.
Anyway, I got Darkbar from wincustomize.org or from here, I don't remember.

taskbar3 doesn't have a "vertical" option, but by defining many rows, and setting it very narrow, you could achieve the same effect.

It's possible to have vertical tasks with taskbar3 and some scripting for now, until if ever it gets fully implemented into the module itself.

The following is untested btw; you may not need to hide the taskbar when you have zero tasks if you have a border or a nonzero initial TaskbarHeight?

Alternatively you can multiply the number of tasks by your task button height, add any padding and size the taskbar each time, and/or also do it this way to autosize an lsbox in which the taskbar is contained.

Well,
Taskbar3 "has" the ability to create a vertical taskbar ;) But it's a little bit tricky.
Here's the setting

with which you can tell how much lines (vertical) your taskbar should have. Default is 1.
Now you only must calculate how much "Tasks" fit vertical in your taskbar

"TaskbarSpacing" should be 0, if you want space between tasks make it in the tasks itself (image), or try out what looks better.
"yourtasksheight" will be the "Tasks"Height
"yourtaskswidth" will be the maximal horizontal "Tasks"Width (less than your TaskbarWidth of course ;))
Play around to get the best looking configuration (all is possible, just try)
Wrap with autoadjust works also if taskbarlines it reached "TaskbarButtonDirection" is then the wrap direction.
I use it with taskbar3-0.306_alpha-3.dll maybe older/newer versions don't have the "taskbarlines" anymore, Taskbar3 changes it syntax so often :(

Andymon

Take a look at this:
http://www.litestep.net/index.php?section=2&action=details&id=343