Looks to me like d.legend is what you are looking for.
Usage:
d.legend map=name [color=name] [lines=value]
Parameters:
map Name of raster map
color Sets the legend's text color
options: red,orange,yellow,green,blue,indigo,white,black,brown,
magenta,aqua,gray,grey
default: white
lines Number of text lines (useful for truncating long legends)
- Bill Brown