The first pic is a tail from another bike adapted to the CB-1. Second one looks like a custom fabricated seat. VERY rare to see anything like what you want. Maybe on the Japanese ebay once in awhile.
Go here,
http://hondacb1.proboards7.com/index.cgi sign up and search old posts for people who are bringing stuff over thru buyers in Japan. That would be your best bet. The steel frame on the CB-1 makes it a fairly easy job to weld tails from other bikes to the frame. You just have to find something that you think looks good with the rest.
Good luck with the search. Keep us posted.
