Hi Chanceh,
If you can download and install RhinoMac WIP, then IFC is an option with my Geometry Gym plugin. You can import and export IFC. Note that as Archicad doesn't have nurbs (to my knowledge), then shapes that can't be expressed must be meshed (which I believe is what the Graphisoft plugin is doing anyway). I do support IFC4 which has nurbs as an improvement, but I don't know when Graphisoft will support IFC4 and if nurbs would be included in their implementation.
Here's an import image.
You can download from
http://www.geoemetrygym.com/downloads and refer to this blog post.
http://geometrygym.blogspot.com.au/2015/09/geometry-gym-mac-plugins.html
The official release of RhinoMac should soon support dotnet plugins.
If you have any questions or suggestions, I look forward to hearing them.
Cheers,
Jon