I contacted Michelin about this last week.
They told me that the 17" run flats are NOT available and they don't have any plans for them to be available this year.
I'm seriously considering replacing the RFT's with 1000 miles on them with non-RFT PS2's and buying a compact spare for the trunk. But that totals out at about $1,500. If I got $400 for my RFT's, I'm spending $1,100 for this change.
So I might keep the RFT's for about 1/2 to 2/3 of their life and then dump them. That way I'll see how much harsher they get as the miles accumulate. I live close to some pretty rough roads and the RFT's are pretty harsh. They are fine on smooth roads.