Hi John / Andrew
In anticipation of the likely new year release of the S-100 80386 board and associated memory boards I was pricing up the cost of memory chips for the 32Mb board and came across what appears to be a recently released chip from Alliance Semiconductor the AS6C3216 this chip (also surface mount) has double the memory density of the chips used on the 32Mb board mezzanine cards and seems to be priced at UK £9.98p at Mouser UK
or $15.94 at Mouser US
Not sure if this is an option this late in the day to either double up to a 64MB board or lower the cost of building the 32Mb board, or maybe even allow an arrangement where the mezzanine cards can be added as funds allow for us more cash strapped builders :-)
regards
David Fry