It turns out that before he died, he was working on a new movie called 'The Dream Machine'. I haven't found much about it's plot yet, but it has been called ' a road movie for robots' and the TVtropes link below mentions it being 'an homage to Astro Boy'

http://tvtropes.org/pmwiki/pmwiki.php/Anime/TheDreamMachine
And looking at the image gallery on the movie's site http://yume-robo.com/ , it's easy to see where he got the inspiration. I just hope the movie gets finished/released soon because it's been put on hold due to financial issues.