Xpantastic!

I have also considered replacing these displays. I see you guys have 
already found out that there is not a direct replacement. However, what 
you can do is look for old cash registers and/or industrial display 
equipment. The NEC displays were used quite a bit in the 80's, and 
there are still some floating around in electronic surplus stores.

Always try to turn your xpander off when not using it because VFD 
displays only have so many hours of use in them. 

Also, the matrix 12/ expander has every chip in a socket. This make 
repairs easy but sometimes the chips come lose in the socket. I have 
repaired mine several times by just pulling the parts out and reseating 
them. (Be very careful not to bend any leads).