Well, there is the possibility to get a Lower than Standard minimum according to EU-OPS. And for EVS the minima are even lower. All according to EU-OPS and CAT I. Usual values for LTS are 400m RVR, for EVS 350m. We have those minima on our charts, however we do use only the standard values and use CAT II/III if needed. No idea what the requirements are to get an approval for LTS.
As for going below minimum, never done it, and don't have any intention to do it except in an emergency.