Something quick and stupid I did for rt_sonoma. If you want to try it, copy the following text and paste it at the bottom of the track's ext_config file. Then extract the files from the attached .zip file. If you are updating from my previous version, overwrite anything it asks.
If you would prefer to display numbers instead of driver initials, go into the extension folder and delete or rename scoreboard.lua. Then rename scoreboard_numbers.lua to scoreboard.lua.
;;;;; SCOREBAORD DISPLAY STUFF ;;;;;
[MODEL_REPLACEMENT_...]
FILE = rt_sonoma.kn5
HIDE = scrtwr_002
INSERT = sonoma_display.kn5
INSERT_AFTER = wdptfncepst
[SCRIPTABLE_DISPLAY_...]
MATERIALS = SCRTWR_DISPLAY
RESOLUTION = 1024, 512
DISPLAY_POS = 0, 0
DISPLAY_SIZE = 1024, 512
SCRIPT = lapdisplay.lua
[SCRIPTABLE_DISPLAY_...]
MATERIALS = SCRTWR_DISPLAY
RESOLUTION = 1024, 512
DISPLAY_POS = 0, 0
DISPLAY_SIZE = 1024, 512
SCRIPT = scoreboard.lua
[SHADER_REPLACEMENT_...]
ACTIVE = 1
MATERIALS = SCRTWR_DISPLAY
PROP_... = ksAmbient, 0.275
PROP_... = ksDiffuse, 0.275
PROP_... = ksAlphaRef, 0.5
[MATERIAL_ADJUSTMENT_...]
ACTIVE=1
DESCRIPTION = digital displays at night
CONDITION = NIGHT_SMOOTH
MATERIALS = SCRTWR_DISPLAY
KEY_0 = ksEmissive
VALUE_0 = 230,173,120,0.011
VALUE_0_OFF = 230,173,120,0.01
[MATERIAL_ADJUSTMENT_...]
ACTIVE=1
DESCRIPTION = digital displays at night
CONDITION = NIGHT_SMOOTH
MATERIALS = LOGOSCRTWR
KEY_0 = ksEmissive
VALUE_0 = 230,173,120,0.005
VALUE_0_OFF = 230,173,120,0