The Lakers are not going to trade Shaq unless they get the other teams BEST player, not to mention 2-4 solid, young players.
Think about it, why would LA give up Shaq for such little in return.
Also, if Shaq retires, he will pull a Hakeem, and just say he is retiring. His deal will remain on the books until it expires, no way Shaq gives up 60 million.
Personally, if the Lakers want to rebuild, trades really aren't the way to do it IMO. At least not involving Shaq. The trade would have to be so large scale, they would be forced to take back some less than attractive players/contracts. It would be better to sign and trade Kobe, where they could choose their young talent, and not have to take back any bad deals.
Also, IF the Lakers want to blow it up, they will have to wait till Shaqs deal expires. Think about the FA splash they will make in 2006 with 30 million coming off the books. It isn't like they are in danger of loosing money the next two years. It would be better for them to just start from scratch (either with Kobe, or players from a sign and trade).