After reading the excellent tutorial at
DoberDawn.com (link at bottom left to How To Dremel Dog Nails) I am sold on filing vs clipping, and happened to have one of these kicking around I use to label housekeys. It is not loud enough to be scary and not strong enough to do damage (never apply pressure! and if you do on this it won't spin anyway).
Following Dawn's introductory process, we have managed to find some of Frisco's nails and zip them even though he resists personal meddling. Of course he made me do mine too so he could watch.
I guess I'd recommend something like this unit, because you can always use it to label housekeys if the dogs don't like it. It's nearly the same price and comes with a lot of spiffy tips.
Amazon.com: HoMedics Style Spa Deluxe Manicure &... We are using the little wee bits.