Moebius Linux is a Raspberry PI armhf distribution built from scratch and targeted to have a small footprint. 20Mb of RAM (with ssh) and a 128Mb SD are minimum requirements. Size, speed and optimizations are main goals for this distro, take a look at it and contribute if you like it
UPMS is based on BSD ports system, it can be used on any FSH 2.x Linux compatible distribution. UPMS have two level of dependencies checking, required and suggested. This two levels makes UPMS to tune all of the packages to optimal or minimal, depend on