Re:Why not create it yourself? (Score 1)

I'm working on a PostgreSQL backed system like this. I'm still at the design stage though, since I'm a shitty programmer and a shitty DBA. I've got a nifty table design that allows parent/child relationships of table elements to be determined by joining a table to itself. I originally intended it to be for managing inventory categories but it's generic enough that the same tables can be used for a todo list.

Don't hold your breath though, it's slow going.