Bolder Sounds has announced the release Thumb Piano. The range of this Thumb Piano is 2 octaves plus a major 3rd. The Thumb Piano was sampled with both plucks from the flesh of the thumb as well as the finger nail of the thumb for a brighter sound. Also each sample zone articulation has 3 round robin samples assigned to it.
Bo Clausen has contributed KSP scripting to the Kontakt version which is documented in the .pdf manual featuring arpeggiator presets and numerous other control features.
Thumb Piano is free. Sampler formats include Kontakt (3+) and EXS24. 101 MB total.