Here is the question, that you 1st must answer. How much are you looking to spend, and what is going to be your run time, because there is no way a shopbot is going to run 8 hour continuous, and new machine may start off that way, but if you are going to run these types of items and hours. You are going to need the BIG IRON...and there are plenty of used machines out there, that for what a new ShopBOT cost, you can get a used CNC, Vacuum Pump and Software for what the 5x10 machine runs. Check it out here are couple of websites..
hell even ebay.com
You can even put in the contract, they the purchase is based on the machine running correctly or they repair the machine at their cost or you can ship the machine back for a refund, I have installed two machines, with these types of contracts.