During the workspace sprint I had several discussions with the Usability expert Björn Balazs (of open usability fame) about how to bridge the gaps between usability teams and developers, how to improve the communication and trust between the two and how to increase involvement.
One of the actions we undertook was a trial run of offering the chance of usability input during the code review process. To do this we have added a usability group on reviewboard which can be assigned to add a UI check to any code checking.
Developers, from now on if you create a patch that has a significant UI change, such as the introduction of a new dialog simply add the group "usability" to the list of groups that should review your code in addition to the normal maintainer group. The usability team will be notified that you want them to review and make any comments we deem needed or hopefully just told the team approve. If you do this, you should make sure your patch on reviewboard is accompanied by screenshot(s). Ideally in the form of "before", "after" where applicable.