I have used a Grizzly commercial sander to sharpen runners, and I know a number of people that have purchased this sander. It works pretty well right out of the box. An advantage of this machine is that it is also a great workshop sander when you don't have ice.
Grizzly G1531 6" x 80" Edge Sander:
http://www.grizzly.com/products/6-x-80-Edge-Sander/G1531/