I currently own and fly a 1963 C model Mooney. No autopilot, not even the old wing leveler. I fly in IMC all the time and hand fly approaches. Not often but sometimes to minimums (just the way weather seems to work around here). I often wish I had an autopilot and all the super fancy GPSS and roll steering etc, etc, etc... but I do enjoy hand flying and disagree with folks that say you must have an autopilot to fly single pilot IFR. You just have to constantly keep training and keep your skills up. I don't fly IMC if I am towards the end of 6 month time period getting in my approaches until I do so. I do more than one or 2 IPC's a year with a flight instructor. And of course, as has been said, a well rigged airplane that will fly straight and level hands off is a plus.