I needed some properly sized human ears for a project, modeling the "fit" of a medical device. I downloaded a model from http://www.3dcadmodel.com/Download-3d-model/Character-and-role/3d-ear-model.html, edited it in Blender, and printed the left and right separately.

The prints turned out great, but doing it again, I would spend time in Blender getting rid of most or all of the "scalp" portion of the ear, and adding a simple, flat base. As is, you end up with an angled, wedge-shaped support which is wasteful. Also, the scale is huge compared to the norms of Blender. It may be worthwhile scaling it down, then changing the unit when processing the STL.

In Blender, I spent time on just one ear. When it was ready, I duplicated it and mirrored the object to make the other.

Blender file is included so you can play with it yourself.

These are fairly low-res, but definitely good enough for my purposes.

Objects were printed on a BFB-3000 Plus, dual head machine, in ABS.