What to do with a result too small to be publishable, but interesting nonetheless?
You can think of publishing it as a short communication, many journals accept this kind of contribution (they can be designated in different ways, depending on the journal). As I recall, the shortest article ever published was of about 3 lines [1] ;-)

[1] F. Lenz, "The Ratio of Proton and Electron Masses", Phys. Rev. 82, 554, 1951.