Most games in the genre seem to have this, and it would be especially useful in Transcendence. It could be based on size (length) and/or mass, with appropriate thresholds. Two categories, gunships and capital ships, would be good enough, but dividing each of those into light and heavy sizes might also be nice. The icon for small stations might need to be changed to a different shape to avoid confusion. Also, particularly large stations could get a larger icon, too.

See also:
containers on LRS are a solid green dot 1.7b2
SRS enhancer should use same icons as LRS
Suggestion: make angry friendlies and escorts different colors on the LRS and SRS enhancer

nms on 5/26/2017 11:41 PM:

Here are the common symbols that are currently used (representing each pixel with 2x1 characters and inverting the brightness for display on a light background):

ship / very small station 3x3
▒▒██▒▒
██████
▒▒██▒▒

  ████    (wrecked 4x4)
██    ██
██    ██
  ████

station 5x5
██████████
██▒▒▒▒▒▒██
██▒▒▒▒▒▒██
██▒▒▒▒▒▒██
██████████

██████████
██      ██
██      ██
██      ██
██████████

stargate 9x9
        ██
        ██
    ██████████
    ██  ██  ██
██████████████████
    ██  ██  ██
    ██████████
        ██
        ██

I think it would be reasonable to use something like this:

gunship 3x3
▒▒██▒▒ (same)
██████
▒▒██▒▒

▒▒██▒▒ (slightly smaller)
██  ██
▒▒██▒▒

very small station 3x3
██████
██▓▓██
██████

██████
██  ██
██████

capital ship 5x5
▒▒▓▓██▓▓▒▒
▓▓██████▓▓
██████████
▓▓██████▓▓
▒▒▓▓██▓▓▒▒

▒▒▓▓██▓▓▒▒
▓▓▒▒  ▒▒▓▓
██      ██
▓▓▒▒  ▒▒▓▓
▒▒▓▓██▓▓▒▒

medium station 7x7
██████████████
██▒▒▒▒▒▒▒▒▒▒██
██▒▒▒▒▒▒▒▒▒▒██
██▒▒▒▒▒▒▒▒▒▒██
██▒▒▒▒▒▒▒▒▒▒██
██▒▒▒▒▒▒▒▒▒▒██
██████████████

██████████████
██          ██
██          ██
██          ██
██          ██
██          ██
██████████████

large station 11x11
██████████████████████
██████████████████████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
████▒▒▒▒▒▒▒▒▒▒▒▒▒▒████
██████████████████████
██████████████████████

██████████████████████
██████████████████████
████              ████
████              ████
████              ████
████              ████
████              ████
████              ████
████              ████
██████████████████████
██████████████████████

stargate 11x11
  ▒▒▓▓▓▓██████▓▓▓▓▒▒
▒▒▓▓▓▓▒▒  ██  ▒▒▓▓▓▓▒▒
▓▓▓▓▒▒    ██    ▒▒▓▓▓▓
▓▓▒▒      ██      ▒▒▓▓
██        ██        ██
██████████████████████
██        ██        ██
▓▓▒▒      ██      ▒▒▓▓
▓▓▓▓▒▒    ██    ▒▒▓▓▓▓
▒▒▓▓▓▓▒▒  ██  ▒▒▓▓▓▓▒▒
  ▒▒▓▓▓▓██████▓▓▓▓▒▒

Even at that size, most stations would still be smaller on LRS than on SRS (their "real" size for functional purposes).