Pinball is an addictive hobby, there is no denying that. I do not have any insight or contacts on the inside, but I honesty could see Stern running a LOTR again.
I think with the delays of the smaller boutique pin makers and the impatience of some (myself included) in this hobby, Stern would have no trouble selling re-runs of their "hit" machines. I don't know if licensing becomes a factor, but I know of many people that would love a NIB LOTR if they could get their hands on one. Also, with the release of the third Hobbit movie, that might be a great time to put them out, just as interest is peaked in middle earth again. If Stern can reproduce for 5k NIB, that sure beats the 8K+ that JJP will command for their machine.