I have a SELECT list with several OPTION elements. Here is my naive approach to styling part of the option text:
But you could always create a Custom select box. Refer the jsFiddle below,
JSFiddle for multi colored selectbox options
// Insert a list item into the unordered list for each select option
for (var i = 0; i < numberOfOptions; i++) {
$('', {
html: $this.children('option').eq(i).text()
.split(' ').join(' '),
rel: $this.children('option').eq(i).val()
}).appendTo($list);
}