This should probably be in the house rules forum, but whatever...
Here's the variant I came up with awhile back, and have tweaked a bit since. It's based on CR, not HD; later editions included turn resistance based on HD after I crunched some numbers and saw that it would work out better (and you don't have to worry about which monsters get it or not). As you can see from the chart, also, there is no upper limit to the roll - there is a chance, however slight, that the low-level cleric can turn the uber-lich.
Times Per Day: You may attempt to turn undead a number of times per day equal to 3 + your Charisma modifier. You can increase this number by taking the Extra Turning feat.
Turning Check: First, roll a turning check to see how powerful an undead you can turn. This is a Charisma check (1d20 + your Charisma modifier + bonuses). On a given turning attempt, you can turn no undead creature whose CR exceeds the result on this table.
There is no upper limit to the CR of undead that a cleric can turn – the table just goes to level+4 – but if the cleric has enough bonuses (turning feats, class/domain abilities, and/or circumstance bonuses), there is no reason why he shouldn't be able to turn something 6 or even 8 levels higher than he is with an exceptionally high roll. We instituted this rule because circumstances like this are extremely rare, and should work toward the player's benefit – if he has gained enough abilities to affect very high-level undead, he should reap the rewards. If your level is 5 higher than the target's, the undead is automatically turned, but it doesn't count against the number you can turn with that attempt. Likewise, if your level is twice or more the undead's CR, it is automatically destroyed, and this does not count against the number.
Turning Damage: Next, roll turning damage. This is 2d6+Cha in number of undead, not HD of undead. Undead are affected from closest to furthest; lower-CR undead are always affected first.
Area of Effect: Turning can take one of two forms: either the cleric can turn undead in a 60-foot cone emanating from his front, or he can unleash a burst of positive energy that affects all undead in a 30-foot radius. Either way, he cannot affect more than 2d6+Cha in undead. You don't need line of effect to a given target, but you do need line of sight (he must be able to see the undead he is turning so as to put the fear of his god into them). Note that if the cleric uses the area burst instead of the cone, he must have line of effect to the undead, but does not need line of sight (since some undead would be behind him).
Effect and Duration of Turning: Turned undead flee by the best and fastest means available to them. They flee for 10 rounds (1 minute). If they cannot flee, they cower (giving any attack rolls against them a +2 bonus). If you approach within 10 feet of them, however, they overcome being turned and act normally. (You can stand within 10 feet without breaking the turning effect—you just can’t approach them.) You can attack them with ranged attacks (from at least 10 feet away), and others can attack them in any fashion, without breaking the turning effect.
Destroying Undead: If your level is 6 or more higher than the undead's CR, you destroy any undead that you would normally turn.
Turn Resistance: Under this system, turn resistance works slightly differently. All undead get turn resistance equal to 1/3 HD (round down), in addition to any turn resistance they have normally (i.e., TR gained from a template). Turn Resistance is added to the CR to determine the CR as far as what the cleric can affect.
Table 1-1: Turning Undead
Code:
Turning Check Result Most Powerful Undead Affected (Maximum CR)
0 or lower Cleric’s level – 4
1–3 Cleric’s level – 3
4–6 Cleric’s level – 2
7–9 Cleric’s level – 1
10–12 Cleric’s level
13–15 Cleric’s level + 1
16–18 Cleric’s level + 2
19–21 Cleric’s level + 3
22-24 Cleric’s level + 4
Etc.
An Example of Turning
Herne the 8th-level cleric is facing a four zombies (CR 1/2, TR +0), pair of wights (CR 4, TR +1), and an 8th-level vampire fighter (CR 10, TR +6). He rolls a 12 on his turning check, which means he can turn anything up to CR 8 – enough to turn the zombies and both wights, but not enough for the vampire. He then rolls turning damage – a 5. Since they are all around him, he chooses to use the 30-foot-radius burst, rather than the cone. Two of the zombies are only 5 feet away, so they are the first ones affected. Another zombie and a wight are 10 feet away, and the last zombie and wight are 5 feet beyond them. The vampire is only 10 feet away, but since Herne didn't turn it, it doesn't factor into things.
All four zombies, since they are 7 levels below Herne, are automatically destroyed, and both wights are turned, but the vampire is unaffected.
