Way back up the thread is Mike Lockmoore's suggestion that conky can do this. Indeed it can, and it's easy. I tested this by writing a mock to-do list in a file named ~/.conkytext and then adding the following two lines to my file ~/.conkyrc:
NOTES:
${head .conkytext 5 (2)}
Here "head" is a conky keyword, ".conkytext" can be replaced with whatever file name you like, "5" is the number of lines to be read from the top of the file, and "2" is the refresh interval in seconds.
Conky is impressively configurable: check out
http://conky.sourceforge.net/variables.html for other things it is ready to display.
With flwm (my favourite), the issue alu mentions is still present: the conky display shows only on the first desktop.