Paint on object in editor and return as texture.

Questions & Answers
1

Hi, how do I make an editor script that lets you paint a color onto an mesh in the editor with the mouse without modifying the mesh, and then return the painted texture. Thanks.

2

Unity does not allow that, at least not without plugins. You probably want something like this:
http://pixologic.com/zbrush/features/PolyPaint/