I don’t know how useful they will be, but there are a couple well-replied posts in the forum about health bars that were fun to read.
[url]Using DirectWaitBar as health bar.]
[url]Health Bars (using DirectGUI ?)]
[url]DirectWaitBar in render]
http://www.google.com/search?q=site:panda3d.org%2Fforums+health+bar