if you are interested...
They happen to have a DC Bambi 0.15cc diesel engine on Ebay at this time, with 5 days left on the auction.
150583457797
it is almost as small in displacement than the Nano engine. A Cox .010 engine has a larger displacement than it does.

http://cgi.ebay.com/Vintage-D-C-Bamb...item230f793805

ref
http://modelenginenews.org/cardfile/bambi.html
The info about filing your own aluminum prop from the blank that came with the original production engine was interesting.