Here are three suggestions to start with in your hunt.  No promises.  I would re
commend writing rather than calling, but there is the risk you won't get a "time
ly" reply.  If you do write, I recommend addressing it to the director, as other
 titles may not be recognized (including "curator") as a specific individual's r
esponsibility, and your letter might sit around forever.

These are from Roberts' Guide to Japanese Museums of Art and Archaeology, Lauren
ce P. Roberts, THE SIMUL PRESS.  I will still ask around.

1. Toyama Art Museum: Toyama Kinenkan Foundation
   675 Oaza Shiroinuma, Kawajima-machi
   Hiki-gun, Saitama-ken
   Japan

tel. (0492)97-0007

...objects from the Italy, Egypt,the Near East and South America...

2. Tenri UNiveristy Sankokan Museum
   1 Furu-machi, Tenri-shi
   Nara-ken, Japan

tel. (07436)3-1511, ext. 7463

...from ancient Greece there is a full range of pottery...

3. Bridgestone Museum of Art
  1-10-1 Kyobashi, Chuo-ku
   Tokyo, Japan

tel. (03) 563-0241

sculpture includes...classical Greece...

these places have a lot more stuff than I quoted, but I'm trying to stay brief h
ere.

Hope this helps/is of interest!

Tim Campbell