Blender plugin based on Blank's obj2col that lets you export collision files for Super Mario Sunshine. Also you can edit collision values.
You need to put the btypes folder into \Blender Foundation\Blender\2.71\scripts\modules
Then just install BlenderCOL.py as usual
You don't need to triangulate the mesh, and you also don't need to merge into one mesh like you did before. You do need to apply rotation/scale before exporting.
This program was based on a python script made by Blank. I just made a blender plugin to work with that script. In future I will add some presets for collision values.