If I wanted a twin (well I do...but...), I'd buy something like an old Seneca II (as it has turbos on and is pretty capable if you get de-ice boots etc...) relatively cheaply. I'd then overhaul the motors, put 3 blade props on, re-upholster and paint. Then depending on how flush I felt, I'd fit a new avionics suite.
So for £150,000 you could end up with a sweet "as new" aeroplane with modern avionics in great known condition.
Yep it will burn significantly more than a DA42 but at the end of the day if one buys a new aeroplane, you're going to lose a shed load of money in the first few years anyway, and that is more then equivalent to the fuel saving.