I would kind of hope that Airlines would not mess around with the SOP's too much. Especially not with important stuff, leave that bit Airbus standard. But for instance: we have an SOP saying that if we are approaching a cleared altitude it is required for us to select vertical speed so that we manage our climb or descent before we actually reach our altitude. This due to TCAS considerations. Airbus doesn't have it, but common sense does mandate it, especially in busy airspace. This is more the kind of thing I was getting at. There are many of these small practical and frankly safety increasing little bits and bobs that will make life on the line easier if you get in the habit of doing them.
What ticks me off personally is when Airlines start writing SOP's into the documentation just because one particular crew on one particular day screwed up somewhere and it had consequences. If something is not a chronic issue you shouldn't write SOP's for an event, just accept that people are humans and despite SOP's they will cock up somewhere. But this is getting off topic.