I thought my PrintrBot needed to stand on something better than the thin metal edges, so I made this simple model
I printed with no infill, and 0 top and bottom fill layers.
with 2 perimeters, theres enough strength to hold up the printer, and enough flex to reduce shaking. however, it will probably depend on the filament you're using.
Actually... I did a new print, with 3 perimeters and scaled it 1.3 in x-direction, and I like how this new print feels. a little less springiness, but still plenty of vibration reduction.