I think what is more interesting are the platforms that are not in that list. Internally we build for 32 bit i686, ppc (32 bit) and s390, but AFAIK we don't release those. We also don't build for ARM 32 bit (but aarch64 will be in future[1]).

Of course this is a lot less than Debian, but we have to carefully choose what we are able to support for customers. This is not a throw-it-at-the-wall approach.

[1] http://rwmj.wordpress.com/2014/03/04/red-hat-64-bit-arm-deve...