Hmm; I suppose you could try setting the MusicBrainz host to 127.0.0.1! You'd probably get a bunch of ugly errors about the server not being reachable, but it would certainly stop the system from getting any MB hits.
We have quite a few old feature requests. In general, all such requests are candidates to be added, as soon as someone finds the time and energy to tackle it. I can't promise anything personally, but options always include putting something together yourself or bribing another developer.