Guido Fawkes was amongst the first to suggest that this might be the most plausible outcome — the
social and economic
liberalism in both parties (the Cameroons and Orange Bookers) could be made to match (with some limits on Lib Dem tax policy recommendations), so the difficulties would be Europe (where they are utterly divergent), and Cameron's reluctance to negotiate on Trident renewal, criminal justice and sentencing, and electoral reform (the Tories are squarely in
favour of First Past The Post).