386SX with 8 SIMM slots isn't that uncommon, but you're right that many of the ones produced towards the end only had 4. The reason is that having 8 isn't that useful, since you can install the memory in pairs and the 386SX can only go up to 16mb anyway.
The 12 slot 386DX board is a bit more unusual. I'd like to see that one in action. I'd really like to see a speedsys of the memory performance on a VLSI chipset that has been tuned. The reason for the 12 SIMM slots is probably that the board doesn't support anything higher than 1mb density SIMMs as it was likely an early one. It appears to have a 287 socket still, which was a trademark of very early 386 boards.
"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium