I had two more ideas for things that I would like to do with Wonders, but I don't see that there is a way to do in the XML. If there is, please let me know. These are not religion-specific.
First, a building that grants +X Happiness from your State Religion in all cities. (I thought this was <iHappinessStateReligion>, but that's for Temples and other buildings that require a particular religion and only affects the city that the building is built in.). Call this <iGlobalStateReligionHappy>.
Second, a building that grants +X Happiness from all buildings of your State Religion. Call this <iBuildingStateReligionHappy>.
Are these possible to do?
They sound pretty easy to add.