Sure, you can build such a hackintosh, but you're behind on OSX updates, you can't update automatically (it may break some of the custom hacks required), you probably can't use auto update.
Also, some of the drivers may have additional bugs due to the ever-so-slight hardware change. In the end, your system may freeze more often, or display weird behaviour.
All that apart from the EULA issue that was already mentioned. Maybe imgix already tested such hackintosh systems and realized that they're just not stable enough for continous high workloads.
terhechte is right about this. To clarify: the reason you can't update automatically is although most hardware is supported just fine, there are many minor adjustments needed, mostly to text files but sometimes to binaries as well to make OSX recognize your hardware. Every time an OSX update comes out there's updates to drivers that overwrite your modified files.
An example of the sort of hack I'm talking about would be a graphics driver that says it's for the NVidia model E532D. Your graphics card is an E532E. You looked on the internet, and you found out they are exactly identical except for branding, so you dive in the driver and simply flip a bit to make OSX recognize it.
