I took the default EQUI_PetInfoWnd.xml and modifed it to show all 30 pet buff slots without having to resize the window. It is actually smaller than the default by a little bit.
This should be pretty patch resistant since I kept it simple, only added the Pet HP% and changed the size and location of the buttons and buff window.
There should hopefully be enough room for the Beastlord warders in there too.
Just unzip into UI folder and enjoy. Hope you like it.