Linux can run on ARM, and if all sources are available, with enough work most disro's could be ported. As far as JoliOS, everything seems to indicate ARM support is very experimental. If you are experienced, with embedded systems, then hacking a project might yield a usable system. It is not the type of project I would want, if I was just getting my feet wet. Also This assumed you have no problem compiling kernels, and preferably cross-compiling kernels. You would have to see if your platform is currently available in the arm kernel sources, or bring in support from another kernel version.
I've been following/messing around with ARM for a couple years now, my netbook is a Hercules eCAFE EX (Freescale I.MX51). As cool as it is, ARM support is NOTHING like the extremely mature x86 and x86_64. Hardware support is extremely fragmented, chipset by chipset specific. As crazy as it sounds... officially supported chipsets often becomes unsupported after just one release cycle. Its like the circa `97 GNU/Linux wild west, but even more fragmented. Remember ARM does not have a standard 'BIOS', so boot methods differ chipset to chipset. ARM also does not have a standard 'ACPI', although some chipsets do emulate it, more support APM.
I understand why you did not know where to ask this question, its because good information on arm is so scarce. It does exist, but only on the 'well traveled' paths. If your starting with ARM, check which distro/version you want and which chipsets/devices it supports. Always try and pick the most supported chipset, the less binary blobs the better. Look for something with some existing community of owners, some experienced hackers might exist. When I get my next device, I will try and get something officially supported by Ubuntu 12.04 LTS.
I hope I at least helped you figure out your direction. If you have platform specific details and attempt that build, I might be able to help if you get stuck.
