Well, considering Gloura comes with some spellcasting ability so any PrC which progress spellcasting is plus. My own suggestion would be Virtuoso (http://www.wizards.com/default.asp?x=dnd/ex/20011207) because it gives you a bardic music abilities (so no need dip into bardic class) and progress your spellcasting fully.<br/><br/>Of course, class overall has lots of crappy class features but through Virtuoso you could qualify for Sublime Chord and other cool bardic PrC's which asks bardic music ability (Virtuoso is expection as it gives you the class abilities). Also I can offer some house ruled fixes to all Virtuoso abilities to make the class actually make bloody sense (song which stabilisizes allies? Okay, nice for 1-3 level range but in +12 ECL char anything which drops you, you do not rise up again one way or another).