I got uploading to a SRAM working from an Arduino Nano! I have also tested properly resetting the 68008 from the Arduino and changing the pins to pull up. I should probably throw together a tiny bootloader and put a 512K SRAM on instead, and I think perhaps a SPLD or CPLD might replace the mess near the RAM more elegantly - a couple of daisy chained ATF22V10s might work well! It all seems stable at ~6Mhz despite being on a breadboard.