I've been looking at the Channeling Companion today as to see where to convert the clerics of Eberron into Rolemaster specialty priests.
I like the rules for them. While the Sovereign Host and the Dark Six have good clerics and dark clerics (evil spell lists abound!). Any how, I think the specialty priest rules are brilliant. At least for Forgotten Realms (where you have a plethora of deities). In Eberron, you have some overlap.
Take the Silver Flame for instance. It might be a light deity (if it weren't for the evil fiend in the flame whispering it's will to its clerics). But the Kalashtar have a light deity to. I was thinking of using regular clerics for the Silver Flame, and using the Light specialty priests for the Kalashtar. At least with the Channeling Companion, you do have to put some thought into how you're using it.