WowAce

What is the enhancement in mind? How should it look and feel?
An option (somewhere, probably at the top of the config window next to 'lock frames' and 'minimap icon') that forces pitbull to treat the raid as being 10 or 25 man.
(specifically: hide the raid groups that aren't part of 10/25 man (3-8/6-8) and use groups with 10/25 man ticked in the filtering tab)

Please provide any additional information below.
Often while we are running 10 mans we swap a character in, but leave them in the raid to keep their buff (for instance, today we swapped out our mage so he could bring his alchemist warlock for freya's drop, but we wanted to keep AI, so we chucked him in group 3)
This made my layout switch to 25 man mode, but with only 11 players. It would have been nice to have a tickbox to hide the single offline player in group 3 and expand the frames back to their 10 man size.

Something like this would be very helpful.

For instance, I would like to make my 25-man raid frames bigger than my 40-man frames, but if you are in a 25-man raid and their is an alternate or d/c put in group 6 or higher, it switches to the 40-man which you dont really need.

Maybe add a key binding to force a 25-man layout.

The guts of what is needed to support this is in now in the latest alpha

This will force 25 man raid: /run PitBull4.StateHeader:SetAttribute("forced_state","raid25")

This will return to normal automatic mode: /run PitBull4.StateHeader:SetAttribute("forced_state",nil)

Other possible values are: solo party raid raid10 raid15 raid20 raid25 raid40

Note that these functions can't be called in-combat. I'll be adding a UI for this but figured I'd point this out for now.