I think that Chris Huhne had a point on Question Time last night: hatred of the Lib Dems among Labour and the Tories in their respective heartland areas (which would account for the great majority of their respective MPs in a hung Parliament) is so visceral that they are more likely to do a deal with each other.
Such arrangements are of course routine in local government; and there is currently just such a coalition at national level in Germany.
Let's face it, who would be able to tell the difference politically between the present situtaion and either a New Labour-New Tory coalition, or indeed a New Tory majority government?
So, although Huhne might not have meant it like this, even in the event of a hung Parliament, the Lib Dems still wouldn't matter.
And has anyone else noticed the serious possibility that they might become an England-only party next time? The SNP could have their every Scottish Westminster seat (and their every Holyrood seat except Shetland) if it made any effort at all, and Plaid Cymru could take their seats in Mid-Wales. Only Cameron keeps them in business in the West Country, where well-known local right-wing Independents are in the offing, including in every seat in Cornwall, all currently Lib Dem held, and in that case pretty much certain to remain so.