Personally, I have trouble seeing how it would be worth more than it would cost to defend it. I want to make another post in Classic Gaming to the effect of, "so you've decided to buy an old trademark." Seems to me it's more trouble than it's worth unless you have a very particular non-financial interest in acquiring these names.
I'd like to see that! The only group to ever come out ahead are the lawyers. It's like WOPR at the end of War Games, sometimes the best move is not to play.