Kobe has won 5 rings for the Lakers, there is no one on thr Celtics that comes close to that, and the Lakers will trade Kobe if it makes them better.
This is not accurate.
Kobe won about 2 rings for LA, Shaq won the others. 2 Rings is only one more then what Pierce has, and Kobe's teams haven't had as many roadblocks (especially injuries) along the way. If Boston had been healthy there is a very good chance Pierce would have 2-3 rings by now.
As for players that are untradable...
Kevin Durant, Lebron James. I think they are about the only two players in the NBA that absolutely would not get traded, regardless of the offer.
The most untradable players Boston have right now would be Rondo and KG. Neither is necessarilly off limits, but I don't see either going.
Rondo is just too valuable to the team right now. He's probably more valuable to Boston then to any other team because they can no longer ride a youngish KG, Pierce and Allen. Both Pierce and KG have but at couple of years in them, and Boston needs a clear franchise player moving foward - Rondo is that guy.
Likewise KG would be tough to pull away. With all the young players we have brought in Boston needs a couple of veteran leaders to teach them the ropes, and there is no better man for that job then KG. Not only is there the value of his 'off court' characterstics, but on the court he is still one of the best 7 footers in the game and he is still the backbone of Boston's defense.
No doubt either of those guys is tradeable for the right price, but what would it take? Boston would take no less then Chris Paul / Deron Williams / Derek Rose for Rondo (and that latter two are 'maybe') and for KG someone would need to offer them an all-star calibre talent.
Pierce is the more likely of the three to go, but I still think they'd need a pretty great offer at this point to let him go. Any less then an 'Iggy' level player and I doubt they'd do it. Especially with Ray gone, Pierce's scoring and versatility are important to this team and difficult to replace.