When Taz and I lived in a little studio apartment he did the same thing!! I would always tell him to STTOOOOOOPPPPPP!!!! I have no idea if he still does it since the cat box is on the other side of the house. Sometimes I'll hear him scratching, but since I am awake it doesn't bother me that much.
I'm sorry the kitties are making you crazy....but you are critter crazy!! LOL
(sorry, bad attempt at a joke. )