I think https://moodle.org/plugins/mod_qpractice might be what you are looking for.
Thank you Tim! I finally found time to take a look and this Plugin looks rather promising. Unfortunatly there is no STACK installed in the test-enviroment. Do you know, whether that combination works well?
In general, it will work. Within the code, there is a good separation between question types, and activities that use questions, which means that if an activity works well with one question type, then it will work well with all of them.
However, there is one detail of that which Question practice does not handle yet - internal random variants.
In Moodle, if you have 10 similar muliple-choice questions, then those will be 10 different questions in a category in the question bank.
However, with STACK (and other similar question types like the core Calculated types) one question in the question bank can have 10 different internal variants.
Question practice does not really understand that yet. In an ideal world it would. In terms of the code, this would require some small changes to the functions like get_next_question and choose_other_question (https://github.com/marcusgreen/moodle-mod_qpractice/blob/qp_1.2/locallib.php#L148 and https://github.com/marcusgreen/moodle-mod_qpractice/blob/qp_1.2/locallib.php#L116).
I am not sure if this theoretical lack in the code will have a significant impact on students or not. It is well worth trying it and seeing. If you do try it, please let us know how it goes.