There is some interest in this from fedora. They are going to have to deal with arm, x32 and arm64 in the not too distant future. That's encouraging them to look at whether they could use multiarch. I gather there is both resistance to, and enthusiasm for, the idea, depending who you talk to (more resitance than enthusiasm so far, but it's early days :-)
We are doing our best in linaro to at least make sure we don't do incompatible things between distros, and there is some LSB work needed to make a distro-independent spec.