And here is another update. We have open-sourced our TendrModelTetra plugin, that generates tetrahedral meshes based on static meshes. It contains a fork of TetGen, with some additional improvements like texture-coordinate preservation of input meshes.
All the mesh generation code is found in the plugin, but the plugin does not generate meshes by itself, as some glue code is required for giving it a static mesh and reserving space for the tetrahedral mesh (our Tendr plugin does as well).
Still, we believe that people can find a use for it, just like we have.