Alzrius
The EN World kitten
Interesting. If you do happen to stumble on it, I would be interested in a reference, but don't bother looking on my account - I don't play 2nd Ed any more, so it's only of academic interest really.
Well, I already went and found it, so I might as well. It's on page 85 of the original version of the 2E PHB (the one with the mounted warrior on the cover, rather than the black-bordered book with the guys kicking in the door), the last paragraph under the "Priest Spells" header on the previous page:
Finally, your DM may rule that not all deities are equal, so that those of lesser power are unable to grant certain spells. If this optional rule is used, powers of demigod status can only grant spells up to the 5th spell level. Lesser deities can grant 6th-level spells, while the greater deities have all spell levels available to them. You should inquire about this at the time you create your character (and decide which deity he worships), to prevent any unwelcome surprises later on.
In any case, I recommend ignoring that rule, as the net effect is to restrict the choice of deities for PC Clerics to Greater and Intermediate deities only - players always plan assuming they'll get to the top levels, and never want to miss out on the big powers!
I personally like the rule, since I think that anything that helps differentiate deities - and promotes role-playing - is a good thing. Handicaps are not necessarily something to be avoided out of hand if you're looking for inspiration for a character.
(One other option, though, would be to have all 1st level Clerics serve demigods, and have them 'graduate' up to Lesser, Intermediate, and Greater gods as they go - presumably moving from the servant deity to the master as they rise in prominence. But I've never seen that done, where I have seen players dismiss the Lesser gods out of hand.)
I think that's a really interesting idea! The political nature of deities - a la The Primal Order - is something I really like, so the idea that greater deities have various servitors of lesser divine status serving them, essentially creating mini-pantheons, strikes me as a very cool idea that helps play up this rule.