We do sell parts to existing customers, but we're systems integrators, not distributors.  We enjoy building components into systems that are more than the sum of their parts.  Frankly if you're just looking for someone to pass along a part in a box to you at a great price with no support, there are lots of vendors doing that.  Of course, we'll always supply maintenance parts and upgrades to our customers, but we're all about building systems here.