It seems odd that for colours, that we use single digits when it is capable to going into the double digits. I would propose that when hitting "red", when doing control-k, it comes up as "01", instead of just "1". I realize it uses more bytes up, and consequently more bandwidth, but I think colour codes need to be standardized.
And since mIRC is also the leading IRC client, there is no reason not to expand into numbers 17 through 98 (99 is for transparency). (I realize they repeat the basic 16 starting at 16 all over again.) That are 82 additional colour slots there. I see no reason why we can't use a 6-bit RGB palette placed into numbers 16 through 79, with 80-82 left blank.
6-bit RGB palette have 4 shades red, 4 shades green, 4 shades blue. 4x4x4 = 64. (that is 2 bits + 2 bits + 2 bits)