I was looking around to find some post processing technique to smooth the items and found a lot of not too expensive sandblasting cabinets.
I wonder if the shapeways team ever has considered to use such a box to smooth the results.
From my surroundings I now that many people I've shown the items were asking for that.
I have a sand blaster. For the things I use it for, I can assure you, a smooth finish is the last thing you will get with it. I seriously doubt any of the mediums other than metal would even survive such an incursion. Sand paper is the route you want to go.