I like the idea, but I'd also like to see something like the dropdown list of colors in the "add" dialog of the nick coloring feature. That'd be very useful for dialogs. No more:
Blue
Red
Green
...

Now you can actually show the color sample, and if someone changed ^k+4 to Teal, well your dialog won't still say Red for it, it will use whatever the color code is set to in mIRC.