I designed a hack to see your clocked-in task on your bar (and not only).
The hack is composed of a few elements, Emacs code that adds hooks for clock-in and clock-out and a code for Xbar.
I have been using this for 2 years, and it's pretty robust. I didn't have time to share it before.
The code is not perfect, if you quit your Emacs, without clocking-out the content of the file will not be changed so you will not see any update on the bar (at least not till next clocking-in or -out)