Here's a 3d model of the famous dog of the artist Jeff Koons. The model has been done using Rhinoceros and results in on single closed polysurface. The object is suitable for 3d printing. Very high details, including where the baloon folds resulting in a very realistic replica. Check the renders to see if the level of details match your needs.
Rhinoceros, STL and OBJ formatis available, but can export other file formats if needed.
For those who want to use the file for render, consider a high number of polygons due to Rhinoceros exportation.