For many years darktable would only run on x86 CPUs that also support at least SSE2. While that is nowadays almost everything looking like a PC it's still limiting. Consequently Roman sat down and started work on dropping that hard requirement. While his work isn't complete yet it's definitely becoming useful. So with a little tweaking you can for example use the development versions on an ARM, like the Raspberry Pi. Together with a touchscreen that has the potential to make a fun little package.
At the moment this is still in heavy development and you have to compile darktable yourself, but we expect it to be ready for the next feature release.
If you want to meet us and see stuff like this live you should come to LGM in London. If you can't go we'd like to ask you for a little donation to the Pixls.us Pledgie. The money collected will be used to pay our stay in London.