No one sems to be considering two real possiblities — that Conservatives and Labour wil form a coalition to stop a second election which might lead to a Lib-Dem majority or that the Lib-Dems will get the most votes and ask for Conservative or Labour support while they form a government.
A Labourparty with the most seats may try to stay in office but would be defeated on a vote of confidence. The Queen would have to choose betwen Clegg and Cameron and would posibly chose Clegg if as now seems possible his party gets the most votes.
The media keep asking Clegg if he would serve in a Labour govrnment. They do not ask Brown and Cameron if they would share power. It is a legitimate question. The polling projections are at the moment hopelessly out of date.