Does anyone know of a serial static RAM I could use for additional PIC
data memory?  I am attempting to alter a pre-existing design that uses
93C66 EEPROMs, so something with the same pinout and bit-banging scheme
would be nice, although not absolutely necessary.  I don't care whether
the SRAM is volatile or not.

The only firm requirements are three pin interface, minimum 64 bytes RAM
per chip (bigger is better), and no write cycle limitations like those
associated with EEPROM and FLASH.

Bonuses would be:
     256 bytes per chip
     nonvolatile
     8 pin package with pinout similar to 93C66 EEPROM

I have searched extensively already, and all that I've found are some
XICOR non-volatile SRAMs that aren't large enough, and a variety of
parallel parts (including the Dallas RAMPort).  It seems like something
like this should exist.  Am I missing something obvious?

Oh, I also spoke with a Microchip tech support guy who told me he's had
the same problem and was also unable to find a solution.

Any help would be greatly appreciated!

Jason Harris