At the risk of this sounding biased, I've had good luck with the used systems from this link. http://www.ibm.com/shop/ca/en/epp

I know it says "IBM Employee Purchase", but they are more than happy to sell to anyone. (sometimes, in the last few weeks of a month, you can get a bit more of a discount by using a checkout code of ibmepp)

Steve Moffat IBM Global Services sjm@ca.ibm.com (204)792-3245