An alternate approach could be as below:

Use a combination of a micro (say 89c51) and hook an external parallel RAM up to it.

Program the micro to receive the data byte thru its serial port/uart, and then immidiately send it to external RAM.

Same way you can also program it to get a data byte from the external RAM and send it out thru the serial.

Then attach this combination of micro and external RAM (that would make you a serial RAM) to your actual application.

That would also be an even bigger hassel :(

But why serial RAM altogether ???

Perhaps you have run out of "Elbow Room" i.e. not enough I/Os are left to do parallel operation, Is it so ??

Good Luck,

Babar/