Dallas could possibly lose Modano,and buy out others.Hrdina and Kozlov offer cheap options of offense and size. As for fitting Guerin in,we will most likely lose Niedermayer,and with stevens likely to retire,and at least 3 players(Oliwa,Langdon,and Marshall) probably being bought out we could fit him in.We will need offense to replace Elias whose return is in question.
I doubt that New Jersey would give up anybody especially useful to get Guerin. I was thinking that the most Dallas could get for him would be a 2nd or 3rd round pick... something along those lines. New Jersey has no reason to give more - by trading him, Tom Hicks saves tons of money that he otherwise would have spent buying Guerin out or paying him to play.
But still, I'd be very surprised if New Jersey tried to trade for him. He'll likely be a free agent in a week, they can take their chances on him and if it doesnt pan out they can get any number of other players.