As we know, since Intel have changed from ICH to PCH we can not fully disable ME any more (at the moment, lets see how far leah gets with the x220).
After checking the different platforms i find out, that the Intel LGA 1366 platform can be used! This platform still use ICH and not PCH.
https://en.wikipedia.org/wiki/LGA_1366 https://en.wikipedia.org/wiki/Intel_X58
Later platforms (LGA 2011, LGA 1356, LGA 1155, ...) are PCH based.
The LGA 1366 (Intel X58) supports great six-core CPUs with 32nm like for example the Core i7-990X (6x 3,47ghz, 12MB L3 cache). Also Xeon X5690 would be great (probably same CPU like the i7-990X.
An other probably FLOSS-possible and even faster platform could be the LGA 1567. This is some kind of a rare platform based on the the LGA 1366 but is been redesigned to support brutally fast CPUs like for example the 10 core (20 threads) Xeon E7-2870 / E7-4870 / E7-8870 CPUs. https://en.wikipedia.org/wiki/Westmere_%28microarchitecture%29 https://en.wikipedia.org/wiki/LGA_1567