Put the Mooney Ovation at the top of your list if high altitude flight is a priority. Once I took my Ovation to FL200 (22,000 ft density altitude) to get over weather.
Being normally aspirated, it doesn't have the (potential) operational and maintenance issues associated with turbocharged engines.
Try this link to goflying.org to see how high, fast and far you can go.
Track Log | GPS Track Log Viewer | goFLYING