There's an update from yaqube for Minimigs with the ARM controller.
Even though Minimigs are quite expensive looks good
http://www.minimig.net/viewtopic.php?f=5&t=183
A new version of firmware files is available. This release requires an ARM controller.
Changes and new features:
ARM firmware - support for:
- MMC/SD/SDHC cards
- FAT16/FAT32 filesystems
- subfolders (unlimited number of entries and depth)
- Long File Names
- alphabetical sorting of entries
- selection of files and subfolders with a keypress
- scrolling of entries with PgUp/PgDn/Home keys
- selection of parent directory with Backspace key
* up to 4 virtual floppy drives
* up to 2 hard files emulating A600/A1200 hard disk controller (up to 4095 MB each)
- optional higher memory card transfer speed (requires simple hardware modification - highly recommended)
- firmware upgrades directly from the memory card
FPGA - new features:
- improved system timing (blitter, CIAs, ROM)
- minor compatibility improvements (CIA access, INTREQ)
- support for two virtual hard disks
- implemented alliasing of custom register space (Kickstart 1.2 now works)
Upgrade instructions in included readme file.