I think it may be becoming more or less standard. It certainly seems so in "Real Housewives of Beverly Hills", and perhaps in California generally. And what they say in Los Angeles today, they say in London tomorrow - and Essex is always up there. I know we have heard it over here now and then but I expect it to be on everyone's lips soon - and maybe in writing, too?
Yes, "I's" is definitely replacing the awkward "my", as in "Jack and I's marriage" - or in general "Somebody and I's something". We've moved on from "between she and I". We are not just avoiding "me" and object pronouns, but we have extended it to "my" (possessives) too. So many of the best things come from that sunny state, not least language innovations.
But, on second thoughts, maybe I am being silly and this has been around for years and I just haven't been meeting the right people. Let me know, please: I don't get out much.