You know all of the nuggets players are pretty pissed right now due to the Melo situation. Their future is pretty uncertain and there wondering when Melo is going to be traded and probably when they are going to be traded. I see no reason at all but the Nuggets would keep Billups. They might also trade JR Smith and Nene as well.
Nuggets Send/ Blazers Receive: Billups
Blazers Send/Nuggets Receive: Andre Miller, Rudy Fernandez, Luke Babbitt and Cunningham
Blazers Send/Nuggets Receive: Andre Miller, Rudy Fernandez, and Jerryd Bayless
WHEN the nuggets do trade Melo they will need to completely rebuild
Being traded is part of the NBA. When a player sign to a team they understand that their name might be mentioned in numerous trade ideas. That's the fine print you never see when you sign. So I'm sure Nene, Martin, JR, and Billups are not worried about being traded. They might worry a little bit but they use that as motivation to perform better. Maybe persuade the team not to let them go.
And besides if they are traded, its a fresh start and a new challenge where ever they land. Shouldn't every player embrace that kind of opportunity?