I don't know why people want to have taskbar and systray in a popup way. It's very uncomfortable... I think VWM, Taskbar and Systray should always stay somewhere on the screen, since you need to quickly click on the tasks tile you want to switch to...
However, if there's enough request, I can made a basic theme with only VWM, systray and taskbar showing in a popup way (without the need of lsbox). I don't see any difficulty of doing such things, and I've already made something like that in the past; but I delete it...

If five different persons post something like "Yes, do it", I'll do...