Craft Wonderous Item
I have seen a great deal of magical holy symbols in my games. Currently my group just found an anhk that has some minor dweomer placed upon it and a name etched into the back in Draconic. Our party cleric believes it to be a key of some sort.
I've also seen symbols that increase effective cleric level for turning purposes (+4 Levels), heal the cleric iff he/she is brought below 0 HP, cast Blindness/Deafness upon non believers who touch them, cast Daylight, etc . . .
Magic holy symbols are exceptionally cool because the cleric has them at the ready all the time. Just use the appropriate feat to make it depending upon the enchantment. Typically it would be a wonderous item.