Here's an interview with Michael Caine (with DIGITALSPY.COMCARS 2) that includes a few TDKR blurbs...
* "I think it will be the last BATMAN that Chris Nolan will make. I never say the last time for me for anything."
* "When I got on the set Chris Nolan said, 'You told someone you're doing Batman!' I said, 'Jesus, how secretive can we be?'"
* "I can tell you we're halfway through it. We finished in England, my next lot [of filming] is in America. And it'll be great."
While Sir Michael's open to doing a 4th BATMAN, I'm pretty sure that there will be a new Alfred when the reboot finally gets here -- which is being produced by Chris Nolan and Emma Thomas by the way. (Thanks to "Pelle" for the heads up!)