Some items from "Some requirements/desires for the automation framework" looks like out of test execution framework.
Item Should facilitate easy interpretation of test "trends"; i.e. statistical-based test results is really far from execution, and it is part of reporting system. I prefer to avoid mixing execution and reporting systems.
Item Collect test output status in a database looks too specific. I prefer to re-define this requirements in something like this "be able to extend save test result in other formats"
Item Able to automatically start testing based on various triggers, e.g. git commit hooks looks too specific also. Git commit hooks just execute command line. So, requesting "initiating start from command line" is more simple. Which other triggers could be used exclude command line?
Items Aware of multiple clusters and Maintains a prioritizable job queue both mean execution framework with dedicated server where multiple configuration and queues are kept and monitored. But with this architecture we are loosing mobility. I think, there is mixed requirements for testing framework and testing system for specific needs.