The real "colour freaks" have tried replacing the bi/tricolour LED with a pair of standard 3mm ones, angled into the front lens.
The definition I'd give to the LED used is tricolour, as it is a 3 wire that enables red/green/both (orange) to be energized easily.
The older red/green bicolour was a TWO wire device with the red and green elements in inverse parallel - AC drive was required to show orange on those.
So with the freeform pairs, or with other tricolours, you could hardmod to...
RED/BLUE - Purple
BLUE/GREEEN - Cyan
Some serious case modders would probably do it!