I've got two of them at the moment, haven't decided which to use.

GU140x32F-7000: 140x32, 115.2kbps serial

and

GU256x64D-3900 (which isn't on their site yet, it's an updated version of the 3100): 256x64 but only 38.4 serial (lame.. half the speed/pixel of the 610A you're using). It does have a normal fast parallel interface though, serial->parallel is an option to get it running at 115.2.