Jon wants a Constitutional Convention. I'm not with him on all of his demands (but agree with most of them). It's certainly in the air, isn't it? Brown's recent noises about entrenching some liberties beyond the immediate reach of Parliament, his need to head off demands for a 'constitutional' EU referendum, the fuss around fixed-term parliaments, and Brown's need for a 'vision thing' in order to get the show back on the road.
This is an interesting idea - for me, particularly, in the context of the view that we don't have a constitution at the moment (and don't need one IMHO).
Would a Constitutional Convention be a good or bad thing at the moment? Well, it could turn the tables on the Tories in the short term. If they want to form a double act with the SNP, it could go a number of ways for them. On the one hand, it could fatally undermine their tradition as the Unionist party - and ultimately the direction could be dropped following a damaging split (yay!).
On the other, there is a certain inevitability that they may ultimately become the English Nationalist Party in due course. Focussed upon a southern suburban and rural power-base, resentfully anti-EU and atavistically right-wing. I'd guess that - if they were to yield to these temptations - they would find that people aren't as keen as they say they are. The Tories are great suckers for placing themselves at the head of imaginary armies (as their obsession with Europe illustrates).
I still think that a nine-and-a-half point plan for decentralisation would give Brown all of the 'vision thing' that he will ever need. It's achievable, it would be progressive, and it would ... er ... reduce the power of the PM and be resisted by the civil service.