I have just released a new *free* plugin for FOP2.
The Queued Calls Counter will add a box to the right column showing the total number or waiting calls in every listed queue.
It is a simple plugin that lets you qucikly see all of the waiting calls you have in your contact center. You need FOP 2.27 or higher in order to use it.
As every other plugin, you can install it via the FOP2 Manager.