I finally was able to do this by following a generic guide for setting up SMB sharing using NOOBS on Raspberry Pi.
I simply used a larger (32GB) SD card and created a directory in root/native file system, upload my ISOs over DHCP (messing around with NTFS is NOT recommended).
It's a rather bloated img, as it was my test/first setup (and includes the full x-desktop that I still need to remove/disable) plus some games I was testing.
I'll get this streamlined/fixed up so I can release something, hopefully actually useful to anyone looking to do the same.
|Darksoft: CPS3, CPS2, F3, MVS|
RGB: RECO v2, HAS v3
invzim: Jammafier v1.6b
XianXi: JNX Raiden, SC Taito Classic, SC Sega System 16/24
Frank_fjs: JAMMA Extender (Special Edition)
The post was edited 13 times, last by jassin000 ().