Elephant ivory for keytops is still available from Germany, complete
with the CITES (Conference on the International Trade of Endangered
Species) documentation.  Mammoth ivory is available as well, which
needs no special papers, because mammoth are no longer endangered.
(They are extinct!)  Elephant ivory is cheaper than mammoth ivory by
about 30%, but a full set  (52 keys) still costs over $1000 US.  This
is for the material alone.  The finished set could run twice that
amount.

Jurgen Goering
Vancouver Island