1)With a desire not to invoke the discssion of whether or not the 8052 is the best MCU to do this, 2)I'm wondering if anyone has any thoughts on what the best approach to a large RAM store would be? I'm looking for something on the order of 512MB (or more) of RAM accessed by the 8052, 3)probably in 8k banks.
1) I have never argued against large DATA memory on the '51, as a matter of fact I have 2Mbyte of flash on one of mine.
2) for the above I have a simple page select register (port 3 on a 8 port Cygnal) and a C routine U8 ReadFlash(U16 offset, U8 page).
What it really comes down to is:
a) how often do you need access (speed) I am in the situation that 99% of the time I need 8-32k and once in a blue moon need the 2M.
b) can you use parallel flash (difficult write, easy read)
c) have you considered the philips XA4xx series ("16 bit '51") they have memory refresh built in. If you use SRAM or flash, have a look at the Philips 51MX and P51C669, they are regular '51s with an extended addressing scheme (23 bits)
3) why banks that small? 64K banks gives a much easier addressing scheme.

Erik