I do not know if anyone is familiar with Blender. But it is an opensource 3d modelling package. I think that if someone made a G-code generation script for it, that it would be extremely powerful. Imagine using Blender, a 5-axis G-code generation script, and Mach. A complete package (less CAD) for $159. Blender imports STL, SVG, DXF, and many others.