I've actually been working on an STV hud that shows only killnotices + HP cross with some generous advice from Wiethoofd -- I've gotten most of the way there but I am stuck on the last couple of items needed to make it a reality.
I've basically hijacked the TargetID panel and removed all other HUD elements, the last two things I need for it to work properly is
a) figure out how to properly reposition/resize the targetID panel and/or the HP cross element so that I can get it in the size and position I want, and
b) change the font of the HP number within the cross such that it matches the POV HP cross
I'd be happy to share this STV hud with the community once it's done but I need some help getting it over the finish line.
More to the point -- I've made my own POV hud that shows only HP and killnotices, if you know how to move all the other elements of your custom HUD off the screen then you can isolate what you want to show.