minifs was made to create monolitic linux firmwares, because in a lot of cases you don't really need "packages" and incremental updates.

minifs download all components tarball, will compile a toolchain for your target platform, a C library, a linux kernel, busybox, and every package you might want, then create a filesystem in either ext, jffs2, or even an initramfs compacted with a kernel.

minifs makes a root filesystem by the traditional way of using a "staging" directory to install everything, then selectively copying items that are wanted, /then/ using a new tool called the cross linker to check what executable really use as libraries, and jetinson everything else.

minifs has been in almost permanent development for the last few years, and has been used in multiple projects. It runs on ARM (Picfure Frames, mini2440, beagleboard etc) and on x86 (from the gumstick sized bifferboard to O2 Joggler, to full fat amd64.

minifs is written in bash. It's pretty easy to extend, and most of the time adding a package is adding 3 lines to the config file. It has inter-package dependencies and a few niceties, but it's really made to stay simple and easy to hack and maintain.