It would be an incredibly clever (cynical?) move by Cameron, especially after manoeuvring Milliband into ruling out working with the SNP.My first thought was 'no chance', but reading the article I can't really find anything argue against. The SNP would be reelected in Scotland for delivering Devo Max. Cameron could kill any talk of him having 'broken the union' by pointing out that he has quelled the Scots will for independence and solved both the Barnett Formula and the West Lothian Question in one shrewd move. The SNP wouldn't even need to back a Tory government - moving out of the way (i.e. abstaining) would likely do the trick.
I expect moving Trident would have to come as part of the deal though.