PolMonitor is a robust hybrid hotbar/monitor add-on that pre-dates many current monitor add-ons, and has been used by many top world raiders.
PolMonitor essentially integrates a hotbar with a configurable monitor on each button. Within each button, you can define what information is monitored/displayed, what spell is casted and on what target if you click the button, what criteria makes that button become active vs inactive, etc.
PolMonitor buttons also support things like spell charges, and Blizzard overlay effects. These can be enabled or disabled per button, in addition to many other things such as button scaling and transparency. Buttons are saved as groups, which are part of Profiles. Each Profile can be assigned individually (or not) per character AND per spec, so when you change spec, your assigned Profile for that character and spec will automatically be loaded.
PolMonitor fully supports OmniCC for button timers, and Masque (ButtonFacade) for button/hotbar skinning. It also allows buttons to have their own custom textures without those add-ons.
For more information, please see the project page at: