vim outliner may work for you if you are familiar with vim.

what i've been using that works ok is gmail tasks. its more than just a tasks list and more of an outliner or list maker.

i made a web shortcut on the desktop to https://mail.google.com/tasks/canvas and it works well for everything i need to keep track of. you will need connectivity to save any edits, but so far that hasn't been too much of a problem.

hth