Giving the plot bunny up for adoption is certainly a good option to lighten your load.
Another thing you could do, if you'd like to write your new plot bunny yourself, is to jot down the idea and then put it aside.
Plunnies do tend to have a horrible timing when they pop up, but they can also be patient.
Some plot bunnies don't go anywhere even if you ignore them, I have story ideas that have been on the back burner for several years and I still want to write them at some point. And I believe that when I will eventually get around to them, I can do better justice to the plotbunnies than what I could have, had I tackled them the moment they pounced me.