Useful information to include:

• Explanation of how the feature/change should work.
  The current smallest font you can use on monitors is 0.5, but I'd like to be able to go to 0.25.
• Some rationale/use case for a feature. My general approach to designing new features is to ask yourself "what issue are we trying to solve" and then "is this the best way to solve this issue?".
  The main reason I want this is that I've been writing programs that make graphics by changing the bg color and printing a space character, effectively coloring pixels. I have some more ambitious ideas than what I've made so far, and higher resolution via a smaller font would be very helpful!
  Example fractal program:
  

Oh, I have not seen that! I'm-a go check it out~

Monitors are already quite expensive. We need to send them over the network (can be a packet up to 25kb) and then render them (pretty cheap if using the TBO renderer, expensive if using VBOs). Doubling the resolution makes this problem 4x worse - definitely something I want to avoid!

changing the bg color and printing a space character, effectively coloring pixels.

Have you seen blittle? This uses the teletext characters to draw much higher resolution images (each character can draw a 2x3 image).