As for printing costs, once I get my own in house printing operation going, my costs will be very low. A "$65" Shapeways shell would only cost $10 or less. Its really amazing how much companies like Shapeways and GoEngineer inflate their prices, because the material costs, even on the highest of high end printers aren't too bad per print. Its just the initial cost of the printer thats the tough part.
Well, if you are willing to "eat" the cost of the printer and only charge for the time and materials, your customers will love you! You also doing this partially as a hobby for your own use, and you have no overhead cost (you're running it from home). Shapeways is a "real" company with overhead costs liek rent, utilities, employee salaries, and amortizing the cost of the equipment and its maintenance. I'm not defending Shapweays' pricing model, but you do have an advantage over them.