IMO, assuming a significant shortfall in seats for the Conservatives, Clegg will be calling some of the shots.
"another election will have to be called"
And the Conservatives would win a clear majority in a second election so Labour will not dismiss the LibDems and fall into that trap.
If Labour wants to keep power (and it does) a neo-socialist Lib/Lab government with Nick as front man is the way to do it. Aside from PR, forget all the other LibDem policies, people aren't that interested in them. But they are interested in Nick and also Vince.
This is a very interesting general election for a change!