From Niall Ferguson:
[I]f Mr Cameron wanted to change the rules of the electoral game in a way that would really benefit his own party, it would not be Mr Clegg he would turn to, but Alex Salmond, Scotland’s first minister. A really bold stroke would be for Mr Cameron to write Scotland off by offering the Scottish National party independence and getting rid of the Scots MPs at Westminster, at which point he would have a majority to govern England, Wales and Northern Ireland.
However, I suspect this is not a road the cautious Mr Cameron will choose.
Full marks for creativity.
Not very much Unionist about it.