I since stumbled upon Giles Bowkett's variation whereby he uses a colour-coded horizontal line for each task. I like it. It emphasises the "chain" aspect and works well within the space constraints.
How do you track of multiple tasks/projects with this technique? One calendar per task? A key/value mapping to replace the cross (e.g. a "G" for every day you go to the gym)? Simply merging them into one "meta" task? Or does it just not work for more than one task?
With the help of Stackdump (https://bitbucket.org/samuel.lai/stackdump/), I've hacked out a useable mirror from the provided XML data dump.