The much anticipated Darksoft Neo Geo AES Multi flash-cart is in the testing phase. It will offer many of the same features of the MVS Multi: ultra fast game loading, multi-slot functionality (transforming the AES into a multi-slot AES/MVS hybrid), graphic or text-based menu, etc. And it will have a new molded cartridge shell. A new programmer was also brought on recently to overhaul the menus for both MVS and AES multis.
Source: https://www.arcade-projects.com/forums/index.php?thread/7201-it-s-coming-aes-multi/
Retro Hardware France has been posting test videos of the cart in action: