Interesting that useful stuff like ECC RAM isn't treated like that.
That being said, it'd certainly be possible to fix this: just ask RAM manufacturers to make their non-ECC memory have the same pin out as ECC memory, with the ECC pins just stubbed to always report that everything is okay. Then all processors could just include the ECC version of the memory controller.
It is fair to say that Intel blocks ECC on its desktop i7 parts for non-technical/business reasons (i.e. so they can sell a higher-profit E3 Xeon if you want DRAM data integrity beyond what non-ECC memory can provide).
I don't think it is. DDR3 UDIMMs, EUDIMMs, RDIMMs and LRDIMMs all use the same physical format.