I’ve been a little to focused on C++ I completely missed and forgot to mention that a new release of Blender, Blender 2.59 was release (*cough* 3 days ago *cough*). A ton of new bug fixes, include one specifically for exporting to Unity, have been addressed. Additionally added support for 3D Mouse(s?), Custom Keymapping, an Ivy and Tree generator.
Click here to download now.
I will check shortly to see if it works “out of the box” with Unity.
EDIT: 8/17/2011 Nope, default export didn’t work. Can’t say I’m shocked.
EDIT2: User woodn has provided an updated importer script. Download it, extract the .py file and extract it to your Unity install directory /Editor/Tools folder, overwriting the existing importer.
After updating the import script it would successfully import dae files, but wouldn’t automatically process .blend files, at least for me.