Hi Markus,
this is not the first time this topic is coming up (I had several off-forum discussions on this as well before).
In a nutshell: I am not convinced that sharing stuff across projects is the best solution to the problem (not that I don't see the need for sharing). Separation of data is a Good Thing and IMHO should not be given up lightly.
So instead of opening up projects the key would be making themselves more powerful and flexible.
using the revision system we should be able to either keep a fixed version of a certain case in a test suite (so that a test run can be evaluated against the case that was current at the time of the run) or always stay at the head of the revision tree to get the latest test case version in all shared test suites.
You already are able create test suites using individual versions of test cases (linking individual test to head revision is a nice idea btw.). You can clone test suites and you can tailor them for individual SUTs, or share them across SUT's.
Coming from a product development background you may feel reluctant to share different products / product lines in one project. Conceptually they are SUT's in the same project for Klaros.
What is currently lacking is the ability to give a project more structure and separate it into logical units.
We are working on this.
Regards
Torsten