A sequel to this question, where I apparently missed the fact that Prestige Paladin has Turn Undead as a prerequisite. So how about it: are there any ranger variants, ACFs, feats, races, or anything else that can give a ranger Turn Undead? Bonus points for pulling it off by 5th or 6th level.
No variant ranger or ranger alternative class feature grants a ranger turn undead. (The variant ranger wild defender (Dragon #324 95) at level 6 gains the supernatural ability rebuke nature allowing the wild defender to rebuke and command animals and, at higher levels, vermin, plants, fey, oozes, and elementals… but never undead.)
Anyone who meets the feats' easy prerequisites can take the feats God Touched and Divine Channeler (both Dragon #305 42) then 1/day turn undead. This is not an efficient use of feats, but it is, so far as I'm aware, the only feat-based way to turn undead.
(Even the Catalogues of Enlightenment—accessible via the feat Planar Touchstone (Magic of Incarnum 207)—for all that the planar site can otherwise do still can't grant the ability to turn undead: the granted power of the domain Sun (Player's Handbook 188), for example, says that it's great turning replaces a normal turn undead attempt.)
Besides using the rules for Items that Grant Feats (Arms and Equipment Guide 128) to create an original magic item that grants the feat Divine Channeler—such an item having a price between 15,000 and 20,000 gp according to the guidelines—, I know of no way to have a magic item grant the ability to turn undead.
In the game's vast collection of monsters, there's probably a creature that can, as a racial ability, turn undead. I am, however, unaware of such a creature and I suspect that were such a creature to possess a suitably acceptable level adjustment of +0 or +1 or maybe even in a desperate case +2 that I would've heard of such a creature. Nonetheless, I'm investigating, but I look forward to answers that can confirm or deny the existence of such a creature.