Ben,
I don't know if there is a bridge between JVM and COM. If you know about the bridge between JVM and COM, you have a solution. If not, the task seems to be unfeasible. I've heard about this project, but it seems it is frozen now, so...
http://danadler.com/jacob/
One possible solution, however, is to create a DLL that can access TestComplete via COM and perform the actions you need. The DLL should export functions that you can call from your Java/Ruby code to control the test execution, e.g. call one function to run tests and another to get results. However, the resulting solution seems to be not very flexible: you will be limited with these functions and with simple data types, as I doubt that you will be able to use TestComplete COM objects in Java code.
