In October 2013 a new flexible Atari 8-bit cartridge named The!Cart was released. Watch this video to see what it can do.
I support the project with video tutorials in this youtube playlist and the software to create cartridge images of up to 128 MB. The software named The!Cart Studio is based on the ideas of the Maxflash Studio and adds additional features like support for up to 16384 entries, import of ".CAR" cartridge files, incremental flashing, and a menu with a Google-like search. It is open source, written in pure Java, and runs fine on Windows, Linux, and Mac OS X. It comes with English and German localization. You can download the stable version or the daily version. The sources are available here. All feedback is welcome!