Project issue tracking across multiple sites

Hi,

Just wondering if somebody can point me in the right general direction for getting project issue tracking setup across multiple Drupal sites.

I've now got about half a dozen Drupal sites running (each with its own different user base, so I can't share the user table). However I would like to allow users to create issues if they encounter a problem, or want to request a feature.

I've been looking at the project module for this, and it looks like it will do the job. However, it would mean that I would have to logon to each site to follow the issues there. Ideally, I would like to have one central projects database where all the issues were stored, so I can see at a glance what's going on, but allow users to access only the issues concerning their own site (without having to maintain another login for the central site).

So, off the top of my head, I could see doing this by:
- allowing users to email issues to the central project database, and then keeping them informed by mail,
- creating a custom module to synch each site's installation of the project module to a central one,
- using an RSS feed to pull each site's installation of the project module to a central one.

... but something tells me that none of these is ideal and that there is probably a much better solution, so I'd be grateful for any pointers.

Thanks,
Matthew