I'm also curious as to when (if ever) this will happen. I used the 2011 bonus to great effect, but things have been stagnant.
Also wondering when, if ever, an AMEX MR-->Delta Skymiles transfer will happen. I wonder if under the new Skymiles system and DL and AMEX being bosom-buddies will make any difference? Seems like they don't see the need currently to offer any transfer bonuses. Have been sitting on my AMEX MR points for 2+ years now hoping they offer one.