If you don't care about integrating into the agenda, this could be quite easily implemented in an org table.
- [O] Dr Wozniak’s tasklist implementation Michal Rus
- Re: [O] Dr Wozniak’s tasklist implementation John Kitchin
- Re: [O] Dr Wozniak’s tasklist implementation Bob Newell
- Re: [O] Dr Wozniak’s tasklist implementation Ramon Diaz-Uriarte