I work for a company building servers for Facebook. They really did try to follow the Open Compute (http://www.opencompute.org/) architecture but ... um, it didn't work out particularly well. They turned to us for tweaking, Quanta for server manufacturing, and us again for rack integration and large scale testing.
<edit> We are the OEM (e.g. design and build) for large scale storage arrays for Amazon & Netflix, too, but not compute servers.
To clarify the pronouns, "they" here does not refer to CloudFlare. It may refer to Facebook, but I hope not as it would certainly be a violation of a NDA.
<edit> We are the OEM (e.g. design and build) for large scale storage arrays for Amazon & Netflix, too, but not compute servers.