Yeah, several companies were making/selling improved replacements; Apple also did make some tweaks themselves, so a given type of machine may well have used more than one revision of hinge. Some of the third-party hinges looked pretty much like the originals but made of, say, stainless steel instead of "pot metal", but I recall one company selling ones that were physically fatter. And, yes, the replacement procedure is absolutely horrible. Here's a writeup from someone who got pretty good at it.
(The machine I had with replaced hinges I had repaired by a company that I negotiated a trade with; in exchange for swapping my broken hinges I gave them another Ti that had a brand-new AppleCare'd LCD in it but had the logic board destroyed by a liquid spill. Since both Ti's had been free it was a heck of a deal...)