What we did was to take a tarball of the x theme, rename it and customise it to how we liked it to look, that way you have all of the cpanel special tags, just make sure you dont remove any of them and you'll be fine, you will have to use divs and heavy css to format some of the elements, for example the "Service Status" page, you dont have control over the outputted table rows so you need to put a div tag around the outside with an id and define each of the elements it writes out to format them how you want, takes a bit of messing but you'll get there eventually.