Thanks for the replies. I found the two in DotF and while i liked the Knight of the Chalice i didn't want to burn a single level of ranger to fulfill the "favored" enemy bit. Plus, to be honest it seems to be a very, very powerful class. d12 hitdice, fighter bab, decent saves (iirc), special abilites, huge damage bonuses to demons and spell casting ability. Sacred Exorcist is close, but doesn't fit perfectly.
I semi-checked out the Witch Hunter, but that really doesn't fit with the campaign. Although if i make my own PrC it will be one of the things i draw on.
The one from Dragon is from issue 287 and is called the Fiend Slayer. Nice little PrC by Monte. It is actually the one I ended up taking. Although, since this is for a high-level character (15th level) I am making the "new" character completes the PrC.
I am probably going to do some work and rework the Knight of the Chalice a bit for his next few levels and make it something a bit more fighter-centric and drop some of the spell casting abilites. Plus, since he already gets a +4 bonus from Fiend Slayer i may drop the KotC bonus to 1/2 of what it is (+1/+1d6 at 5, +2/+2d6 at 10).