There are literally thousands of skins available, so your customer is likely to find one they like. If not, I've created more than a half dozen skins/layouts for DNN web sites, from simple to fairly complex, and it really wasn't that difficult. All it takes it some knowledge of DHTML and CSS, reading the skinning documentation, and browsing through a couple of existing skins to get an idea how it's done.
Meddle not in the affairs of dragons, For you are crunchy, and good with mustard.