Do items that increase Effective Cleric Level Stack

[Balthizar]

Looking to gain confirmation if Items that grant "effective Cleric level" increases do or do not stack. would just like to see people confirm this for me.
My DM does not know, so if i can get at least 5 people telling me yes he says that i can stack them

[Biffoniacus_Furiou]

Rules Compendium page 21, Bonuses, under Stacking:
"Untyped bonuses stack unless the bonuses come from the same effect."

Two of the same item that grants an untyped bonus would be the same effect and would not stack. Two different magic items based on the same spell that produce an untyped bonus would not stack, as the effect of that bonus is the spell used to create the items.

Items that grant a higher level of Turn Undead are not based on a particular effect, apart from Turn Undead itself, which they explicitly stack with.

Many magic items that grant a higher level of Turn Undead are not expressed as a bonus and thus would not fall under the rules for stacking (or not stacking) bonuses:

"If you can turn or rebuke undead, holding a scepter of the netherworld allows you to do so as if your level in the relevant class were three levels higher."
(Phylactery of Undead Turning) "This item is a boon to any character able to turn undead, allowing him to do so as if his class level were four levels higher than it actually is."

Those don't say "+3 levels" or "+4 levels" they're just a flat increase to your effective class level. There aren't many comparable effects, but even if there were, it doesn't fall under the stacking/not-stacking rules.

If you're going for maxing out your Turn Undead effectiveness, be sure to get a Rod of Defiance in MIC.