i have seen those mini-rollers on tv that have the plastic shield that are supposed to let you roll very close to something like a lightswitch cover. do these work?
I would just take the covers off and roll up to them with a regular roller. These items are just gimics and usually don't work as great as they show an TV.
its allways quicker to take off switch pates and door knobes then to tape them up or worry about getting paint all over them. i dont tend to by that stuff off the tv