It is possible to change the default chat color to the yellow text used for item links.
To do this, simply type the following into the chat window:
The bold text above can be replaced as you wish. The alphanumeric code between ($?) and ($$) can be any number or alphabet, so long there are a total of 21 characters. So far, changing the code doesn't seem to make a difference. If the number of characters is not 21, then the code will end up showing in chat instead of changing the text color. The (ItemName) section can be changed to whatever text you have in mind.
Thanks to Cloak of G1 forums for sharing this.