There has been some cooperation in the past (I'll have to look it up),
this is why I know that it is not easy and a wide field. For most people, the 
quality aspect of software development is not what they are interested in 
initially. And in general higher quality means defining it, measuring it and 
funding it and overal in IT this is often not happening. It feels like in this 
field we are trying to get the basics right. My idea is more along the lines 
to teach and enlight people about the specific quality aspects that a nice 
Free Software and community development can contribute to IT.

I think, also responding to points made by Vitaly and Paul, that software quality guidelines are mainly the responsibility of the projects. As for software quality in Free Software:

The ultimate goal of the free sofware movement is that all software should be free software and respect the users' freedoms. A sensible sub-goal is that producing free software should be the industry standard whenever new software is commissioned.

Thus, if an organization needs some software and finds it does exist, it would a) hire developers or b) commission another company to make the software, with everyone taking for granted that of course it will be free software.

Then, as in all other kinds of engineering, the contractors would be expected to adhere to recognized industry-wide quality standards, which nowadays means coding guidelines, linting, code reviews, automatic testing and many other things.

A lot of existing free software does not adhere to such standards mainly because it's old-ish and not made as you would do a similar project today. But that is not specifically because it's free software - the same is true of a lot of proprietary software as well. It's more because it was built on practices that were normal at the time but considered legacy today.

So a lot of the work to improve quality in free software is political - and is that of changing people's attitudes to make free software the automatic default in all software procument. This is going to be a process, because in many areas the software needed to support daily workflows and infrastructure doesn't exist as free software yet. So decision makers need to be convinced to start that process.

And then, the issue of quality in free software will become the same as the larger issue of quality in software in general.

Best
Carsten