The idea is to have a single procurement system to keep down costs associated with design and purchasing by 2020. Starting this quarter of 2017 they intend on having their first round of submissions based on a 20 page spec sheet. The nations have agreed to not propose specific solutions, only state requirements. This should produce a massively diverse array of extremely small production test samples from the various manufacturers.
You can find out information about the joint effort here:
In particular this:
Note that the joint effort is far larger than just uniforms.
Interesting and very sensible!