>Unfortunately I don't think it is quite as simple as that, from what I understand that exporter to SolidWorks that you are talking about is not a self contained export module that I could use but rather an interface to another export library called Datakit.

I see, I think Datakit is also what Rhino is using, last time I tried i was not that happy with it, but it maybe improved by now..

>I'm pretty sure that SolidWorks for the past several years now has included a .3dm import module as a standard part of SolidWorks. Does that not work properly for you?

Corect and it does work just fine for me, in fuct geometry created in Rhino some times is not recognised by SolidWorks, when I open same .3dm in MoI and save out from MoI then it works just fine with SolidWorks.
Have not idea why but it suits me... (MoI Magic)