To make a source like they're talking about would probably involve either spallation of a heavy metal target with protons (see the oak ridge SNS), or in-flight

To make a source like they're talking about would probably involve either spallation of a heavy metal target with protons (see the oak ridge SNS), or in-flight decay of muons (fermilab). The main (far) detectors would presumably be on earth where background isn't an issue, but neutrino experiments typically also have a detector near the source also. That would probably have to be underground. Some numbers for reference: the SNS delivers MW levels of thermal power to a 20 ton mercury target, which is circulated as it's own coolant. Just the target itself would be a monumental undertaking, and we havent even mentioned the massive proton accelerator needed at the input end. Accelerators also tend to be very heavy because of all the magnets, and they are very sensitive to misalignment, so the surrounding building will have to be well made assuming the seismic situation is workable. It would be great to focus our resources toward being able to do this sort of thing more feasibly. However, this project is well beyond the scope and budget of NASA. It would take concerted political will and military levels of funding sustained over decades to build up the underlying tech. I would love to see this reprioritization, but i have no expectation of it happening in my lifetime.