I haven't found another person like that yet while exploring the wasteland.

I wouldn't mind paying some caps to become idolized by the Powder Gangers, for instance. (No more annoyances while exploring and roleplaying.)

Would be kickass if they have one guy like that for every faction. If you come across them on your journey and travels, then please list them here for the benefit of us all.

Interesting, what's the guy called? I might steal his script for a mod of my own.

In the northern part of the Strip is the Vault 21 hotel you have Sarah, giving her a bunch of Vault suits increases your fame on the strip.[after giving her about 40 she'll also sleep with.you] The rep boost appears minor though and only once appears after giving a large number to her.
A worn of warning some people encounter a bug where she'll only present the option to take your vault suits once, so you may want to stockpile them.

If you donate meds to Julie Farkas at the Morman Fort it will increase your rep with the followers, which is a VERY good idea because your given a special lab coat that grants +10 Medicine and Science.

The Boomers will accept Scrap Metal for Reputation.

Nice, these are all good so far. Keep 'em coming!

Thanks for contributing.

The Boomers also take missiles (possible unlocked after cleaning out the fire ants)

NCR and CL both have reputation boosters. NCR take NCR dogtags in Camp Forlorn Hope I believe. You can also trade these tags for caps or items in Cottonwood Cove. It's like 1 tag for 10 caps, or 3 tags for something like a frag grenade. The guy that gives equipment also lets you teach CL stuff, like the Powder Charge schematic (found in NCRCF), or how to disarm frag mines. All of those increase rep.

Likewise, you can loot ears from dead Legionnaires. I haven't found where to trade them in, though.