Given that MS is basically abandoning WMC I doubt this will happen, but I would love to get a WMC Extender app for RT - or for it just to have extender built in.
I was looking at Win 8 upgrade choices today and it stated the following:
"Windows Media Center license sold separately"
Doesn't look like they have abandonded it completely. Just deploying it a different way. I will also need extender access if I upgrade to run PlayOn.