It has not been tried in the area as far as I know.
I'm hopeful an updated MWL will happen soon. I worry about custom ban lists because it is another system on top of normal deck building rules and the MWL. It starts to add up for new players wanting to join in.
The usual group that plays in Berkeley/SF has a sort of understanding to not play the perceived Negative Play Experience decks in GNKs and casual nights. We are still competitive but we just try to not play things that put people off like 24/7 and Sifr. I've been playing a silly Mushin Tennin deck for example (I lose a lot of games but it's all good). If a new player shows up with Sifr and 24/7, it is no problem.
Of course, for Store Champs, Regionals, and above, anything goes.