Complete Mage is out.....
Saw a couple of nice things mentioned on the boards; must get this book.
There was one feat I liked the idea of which made you even more specialised as a mage. I think you had to give up another school of magic and one slot/spell level however gained 2 slots/spell level of your chosen school.
They also did the PrC's based on specialist mages which looked really interesting.
Must get this book.....