There are ext2/ext3 drivers for windows... just sayin.
Another robust option might be a big raw tar archive, it was made for serial seeking, after all. (Tape ARchive)
Just observations, seems to work fine, or will once I can lay my hands on a RTC.
Then I'll get it in the car and replace my current MS2 sequential setup.
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.