Yes, I do research in developing my game and campaign. Nope, no 4ed. There are actually a number of really odd gaming systems out there, and when I need inspiration I go to one of them (the best way to have people think you are original is to steal material from some source nobody recognizes). I found this in a rule book given to me.

Troll
A Troll is a good 6 cubits high (9 to 10 feet). His distorted face and greenish body make him positively frightening, though he is a kindly soul who enjoys the companionship of animals. His body spontaneously reacts to its environment: in the spring, small flowers bloom on his legs, while in the fall moss covers him from neck to toes. Many animals live on a troll's body, mainly birds, which can nest in the thick mop of what passes for hair. Calm and always ready to help Nature's allies, trolls often come to the assistance of sprites or giants. Trolls can however become aggressive in the presence of fire. They can't stand to see a torch or even the spark of a tinder-box. In such cases, a troll will become excessively violent and will do anything to put out the fire. Trolls are Wonders,
"Agone," by Multisim Publishing (2001)

Nope, this is not the troll in my campaign. I just wonder if anyone out there has turned a viscious nasty evil malignant monster and turned it into something that would sing and dance with children. Me, I believe in the sanctity of monsters too much to do such a dreadful thing. I will put friendly encounters in a scenario, but nothing as horrible as this.

I haven't completely revised a monster to make them benign, but I have created instances where I've turned a monster on its ear, so to speak. Especially since I DM Planescape, where often things aren't what they seem.

We did have a party that befriended a troll in the original Temple of Elemental Evil -- I still remember the ranger and the troll holding the doors against the invading ogres -- sort of a "we're all in this together" thing.

And we do have a campaign that has a LG Green Dragon NPC -- alignment changed by magic, though.

That troll you mentioned reminds me of books from my childhood, like Giant John and The Laughing Dragon

Nope. Not my troll. The creature described by those rules sounds more like the sort of thing I would feed to my trolls.

My trolls were more or less inspired by this piece of fantasy art. (Courtesy of PMZG game studio.) Trolls are actually an apex predator in my campaign setting. I doubt they would fit in game settings that more closely resemble the cannon D&D worlds.

My Shadowrun experience has made me a fan of nice trolls (who wouldn't rather have one as an ally after all?) and i have made a couple of good aligned Troll NPCs but as a race they are as icky as ever. I do kind of like this nature loving type of troll. I have seen depictions like that where they resemble something between a "traditional" Troll (In D&D anyhow) and an Ent.