I can say the COLLADA/KML support is still on my ModelConverterX wishlist. Not that much progress though yet...
1. Edit the object in Sketchup (Free Version)
2. Export it as 3D-Object (KML-File)
3. Use the free version of StuffIt Expander 2010 für Windows
(Search for stuffit 10 windows in google, you get it e.g. hereChip.de)
4. Open the KML-File in Stuffit
5. Search for the DAE-File which is what a surprise included in the kml-file and extract it
It did not help me with my current problem, Arno will do with a new version of ModelConverterX, but perhaps somebody needs that trick in another context.