I tried to get the Newton SRAM card that you talk about by calling CDW
computer discount warehouse but they stated that Apple has stoped making them
back in October '94 or so.
I have a catolog from Computability, March 1995, that lists SRAM at:
New Media SRAM 1MB type II .... $159
2MB ......$269
And to call for cards of 4MB
Their phone is (800) 896-1334
Rod