Dolphin Templates are designed around several pieces of code and default pages. With D7 there are included in the download some basic instructions on designing templates. The principle items you would be dealing with are the header and footer files (where simply adding or removing some lines of code allows you some nice flexibility in design) the Default page which generates the necessary code to create all the pages which are not hard-coded (the page designer uses these as well) and designbox.html see more templates for your blocks and finally the CSS styles. Many pahp pages also have specific coding for the page layouts as the pages are fluid (blocks can hold different information depending upon what your end user selects for display). The Index page is probably the most flexible as it is the only page using the promo block. The promo block may be removed, edited to hold almost any standard html coding you'd want, and much more. The menu can be placed just about anywhere you'd like.

As previously mentioned, you'd probably be way better off hiring someone to custom-design a template to your exact specifications so you'd have a one-off product and site. After all, I think your mention of a totally different design would be a great seller just negates your idea of having a different looking site. After all, if some tottaly new design that is so different from the "usual" designs sold like hot cakes, then wouldn't EVERYONE suddenly have the same looking design once again?