Hi! I'm aware that you've been experimenting with LESS and Plone. There's any development about this? This year we will engage some major change in the themes of our biggest Plone deployments (over 400 sites) which share the Plone theme, but with some distinctive differences each (colors,etc...) and Diazo is probably not the best idea. Thanks in advance!
LESS is never going to be part of Plone core. It doesn't make a lot of sense. But when you do Diazo (pure or plone.app.themeing) theme a pre-processor is a fantastic tool. I use LESS (though compile it to CSS anyway before going to production) whenever I do a theme. But I don't do Plone themes in a conventional way any more, only Diazo. I don't know why you think it is not the best idea for your case. It's the same as plone theme — you put it into the version control system (git for example) and then update your sites when there are changes. You could probably come up with some idea of using Dropbox folder on all of those machines so that whenever one theme is updated the change is pushed to all 400 sites. But you still have the ability to make some site-specific changes in a separate LESS module for example.
But, getting back to your question — no, there is no activity going on about LESS in Plone. Hope this answers your question.