I think the method you suggest there is way too long to be useful. Something like that will very quickly become too long if you want many colors in a line. Yes, RGB is often suggested and might work, it needs to have some good way to handle it without it taking up anywhere near that much space. RGB converted to Hex without commas and you'd at least drop it to a maximum of 7 characters + a control code. Still rather large, but better than a max of 9 + a control code or multiple characters for an identifier like you show + 2 commas.
Example of yours with Hex (using Ctrl-R for RGB even though it's used for Reverse... not sure what's best for a control code):
echo -a 5F6A470this 1622888is 3E1D616text 97E061Dwith 2844D8Dcolours
Much shorter. And it could be done with even less by using base 26 (A-Z) or base 36 (0-Z) -- 1 character less for each color.
In any case, that's just an example. I'd rather see something short like that than a long drawn out line like what you were showing. And I'm sure there are better ways still that can be used than what I'm showing here and issues involves with using this method. Whatever method is chosen will need thorough testing to determine if it's a good way to handle the colors.
