I have hardwood floors too, and this is what I did. While bargain-hunting at Tuesday Morning, in the kitchen section, I saw a pair of thick, pebbly-textured green potholders made out of melt-proof SILICON! I bought them to use at the grill, thinking it gets saucy and sloppy, these would be easy to wash.
Then, while sewing one day, and chasing my foot pedal under my table, I remembered those pot holders in the drawer outside! They have sort of a tacky surface. I grabbed one, put it under my foot pedal (it's roughly the same size as my big Pfaff pedal), and I've been happy ever since! Hope this helps...