Implementing your own shortcode is trivially easy, so if you have a syntax highlighting package (there are several available), it'd be short work to wrap it up in a CFC that the shortcode engine can use. Basically you just need something like this:

function highlight(attrs, content) {
    return myHighlightingCfc.highlight(content);
}
sc = createObject("component", "shortcodes");
sc.add("time", highlight);

sc.process(myContent);

Obviously the actual implementation of the method will depend on the highlighting package you selected.

ThomasB