Nope, sorry, I (for one) have no advise to offer for those wanting to use gphoto2 on their N800's other than the 'community' advise offered on this thread e.g. make sure that you have 'USB host' enabled, and (supposedly) to use a script as was originally suggested by one of the posters. More generically, on my Nikon cameras, I have always been told to insure that I fully-specified the camera make/model on the command line.

In my own experiences, I have had success on my desktop, but only partial success on my N800, and no success at all on my NSLU2. This tells me that not all 'USB' devices are the same, even if the version of gphoto2 is supposedly 'functional'. Perhaps a never version of gphoto2 will eventually solve our problems?

P.S. I note that you have also posted to the gphoto2 mailing list, which is a good idea -- even if I have also done so in the past.