Drawing a Range Icon in 3D Space

This is bigger than just range icon's but that is what I'm after and hopefully a visual people understand here.

There have been quite a few questions and answers scattered around the forums and here but I'm looking for a deeper more complete, final answer.

• I do not want to flatten a sphere because it creates a lot of extra geometry (the more round you want it the more 'sides' it needs.)

• I am trying to avoid using a texture on a 2-tri plane because my range icon may render larger than the screen and I would have to settle for either a huge image or a blurry edge. Also, I may want to animate it like a radar read-out (you know the classic circle with a line rotating with a fading trail)

• I have seen answers which re-direct to Mesh, and I am no apposed to generating something with a lot less geometry than a sphere, but again, to make it look like a smooth arc, I need a lot of 'sides'.

• Projectors create a lot of draw calls and are still textures, so share the same problem regarding resolution

I have read hints of deeper techniques. So what other options are there to draw (literally) a nice smooth sphere icon that ideally projects on to an uneven terrain.

This blog is interesting and right online with this question: http://www.everyday3d.com/blog/index.php/2010/03/15/3-ways-to-draw-3d-lines-in-unity3d/