Angelic Wings?

[Cheesegear]

You could also try Rainbow Savant (Complete Divine). However, two problems;

You need to be a a Wizard (Sorcerer might be better) to get into the PrC. Not such a bad deal. Since it gets Cleric spells as well. Second, the Rainbow Savant is flavour/world-specific. Your DM needs to be reasoned with if you want this class. Especially since the text of the class (not the table) makes it fairly powerful as the text says the class gains +1 arcane spellcasting every level. Wheras the table skips a few levels. Official word says text trumps table.