A coincidence, I've been looking for these for my parent's washer as well. I found some at MSC Industrial for about $24/4 as well as Satfrat's atlantavibrationpads @ only $17/4. But I was looking at the 3x3" size since they are all rated at 50pound/sq in so the 3" size would support up to 450lb.--their washer is 250lb. So Satfrat, do you have a monster washer?!
And how much isolation do they provide: a little, moderate, or mucho?