Michele,
I think your question may be slightly ambiguous. It appears that Geo interpreted your request for “suggestions on how to get vector art logos to import into Sketchup with little to no clean up,” as asking how to come up with the vectors in the first place–how to convert raster images into vectors. It sounds to me like you’ve already got the vector logos and just want to “get them into SketchUp” reasonably intact.
It’s a problem controlling the conversion of curves made in a 2D drawing program to the kind of straight-line, segmented curves used in SU; in my experience coming from CorelDraw via dxf, it isn’t as simple as one segment per node: sometimes curves come across chunky and oversimplified, and sometimes they seem to have a thousand little bitty segments, sometimes broken into separate entities and sometimes with gaps or bad intersections.
I have grown increasingly confident in my ability to trace intricate curves using SU’s limited drawing tools–primarily the Line and Arc tools–and you can exercise far greater control over segmentation. Additionally, there are various plugins to help with tracing curves and controlling their segment spacing. Perhaps you should consider importing the logos as traceable images and tracing them by hand in SU. You certainly have the greatest control over the outcome that way.
Incidentally, may I inquire why you elected to produce your 2D signage with a 3D modeling program?
-Gully