I think the KOMA documentation puts it very nicely, when describing which title is created using \maketitle
and how it differs from the book cover:
A cover is actually something that should be created in a separate document. The cover often has a very individual format. It can also be designed with the help of a graphics or DTP program. A separate document should also be used because the cover will be printed on a different medium, possibly cardboard, and possibly with another printer.
This means: the layout/formatting of the main document has absolutely no bearing on the layout and formatting of the cover.
Here is one attempt but if you are in a hurry use a WYSIWYG software.
\documentclass[tikz]{standalone}
\usepackage{fontspec}
\setmainfont{Myriad Pro Bold}
\usetikzlibrary{calc}
\def\myhbleed{10mm}
\def\myvbleed{10mm}
\begin{document}
\begin{tikzpicture}
% Left page
\node[anchor=south west,inner sep=0,outer sep=0,minimum height=297mm+\myvbleed,minimum width=210mm+\myhbleed,fill] (lp) at (0,0) {};
% Spine
\node[font=\Huge,rotate=90,anchor=north west,inner sep=0,outer sep=0,minimum width=297mm+\myvbleed,minimum height=15.4mm,fill,text=white,text width=280mm,align=left] (spine) at (lp.south east) {Dark side of the Moon\hfill Pink Floyd};
%Right page
\node[anchor=south west,inner sep=0,outer sep=0,minimum height=297mm+\myvbleed,minimum width=210mm+\myhbleed,fill] (rp) at (spine.south west) {};
%Decorations
\node (flogo) at ($(rp.north)!0.3!(rp.south)$){\includegraphics[width=11cm]{dsotm}};
\node[text=white,align=center,font=\Huge] (ftitle) at ($(rp.north)!0.7!(rp.south)$) {Dark Side of the Moon};
%Actual A4 page size + spine + A4 page size - Remove before sending to printer
\draw[red] (\myhbleed,0.5*\myvbleed) rectangle ++(210mm+15.4mm+210mm,297mm);
% Outer guides - Remove them for full picture
\draw[ultra thick] (\myhbleed,-1cm) node[below] {A}-- ++(210mm,0) node [below] {B} --++ (15.4mm,0) node[below] {C} --++(210mm,0) node[below] {D};
\draw[ultra thick] (-1cm,0.5*\myvbleed) node[left] {E}-- ++(0,297mm) node[left] {F};
\end{tikzpicture}
\end{document}
Best Answer
Here is a poor man's solution! Cover and title pages should ideally be designed by a graphics artist, as most of us are really challenged in this area! (If you have not watched this brilliant TED Talk by Book Cover Designer Chip Kidd, I advise you to watch it as you can gain a lot of insight into book cover design).
The code follows: