I love melodies played on the cello!
I also see a lot of cello solos accompanied by piano - usually the piano is playing in a higher voice, so just the opposite of cello as accompaniment.
If you ever learned something like Fiddlerman's A Tune a Week #35 - Song From a Secret Garden, there is a great YT Video Channel, "Play-Along for Cello" that has animated Cello notation to read, but you hear the piano accompaniment!
So, this is just the accompaniment - you have to play the notation.
I think it would sound lovely together!
I'm not playing a cello, but having fun playing lower than Viola notes with my low F string, plus I have a an octave pedal (haven't recorded anything yet) that puts me in the cello range.
I should consider this, too - thanks for the idea!