The development of color on the Nipkow disk made some progress, see:
http://www.nbtv.wyenet.co.uk/hot.htm
and
http://www.copycoder.com/phpbb2/viewtopic.php?p=126#126
(Mickey Mouse on the Nipkow disk in color.)
My own mechanical TV set is disassembled now. With a little help from my friends it will get a new and professional looking wooden house.