Be very afraid of the things I decide to do to kill time at work.
Very (VERY) large circular health meter as a proof of concept for circular progress bars. In order to try it out you'll need to add an include to your eq2ui_mainhud.xml for the eq2ui_mainhud_health.xml, then just /show_window MainHUD.Health. The alignment of the progress bars isn't perfect, but it's good enough to show that the idea works in practice. Enjoy!
P.S. I may, at some point, turn this into a player window mod...I've got an idea for the layout, but after doing all the math required to get this thing working right I'm in no hurry to do it again.
Edit: Special thanks to Perdition for pointing me in the right direction with the progress bar styles and Deathbane27 for helping me rid myself of the annoying overhang problem I was having.