While this may not be of any real help, Linda Young might have her student
contact (by snail mail) the owner of the River Shack Tavern, on the banks of
the Mississippi River here in New Orleans.  They bill themselves as the "Home
of the Tacky Ashtray", and indeed have the most astounding collection of
ashtrays I have ever seen.  It is entirely possible that in the process of
collecting, the owner may have become somewhat expert on sources.
 
The address is:
The River Shack
3449 River Road
New Orleans, LA  70121
 
 
Good luck