Like Werner already wrote, you may put \title{<title>} into the document files itself instead of the preamble. If you are using, e.g. babel shorthand at the title, this is even a very good idea. Otherwise you'd have to activate the shorthand before the title and deactivate it after the title. So moving \title{<title>} (and \author{<author>}) after \begin{document} should be recommended.
Instead of creating a package (aka style) you can even create a wrapper class myclass.cls. To do so begin with:
\ProvideClass{myclass}[2011/11/07 v0.1 my first class]
\LoadClassWithOptions{article}
With this, your class is similar to article, because it simply loads class article with all the options given to your class. We call such a class wrapper class.
Now copy everything in the preamble of your document to myclass.cls. Next you should replace \usepackage by \RequirePackage at myclass.cls. And you should remove loading of the package inputenc because the encoding is not an attribute of a class but of a document. Because inputenc has been removed from your class you should make it 7-bit-clean. This means you should e.g. replace ä by \"a. Maybe \RequirePackage[<language>]{babel} should be removed from your class too. But if the class supports only the languages you've given as option there, this is not a must.
At last you should add \endinput at the end of the class file. This is not a must, but it's nice to have.
After this, all your files may be:
\documentclass{myclass}
\usepackage{selinput}
\SelectInputMappings{
adieresis={ä},
germandbls={ß},
Euro={€},
}
\usepackage[english]{babel}% use every language you want
% You need nothing else, because everything else is at `myclass.cls`.
\begin{document}
\title{Title <nr>}
\maketitle
Text of document <nr>% or \input{document<nr>}
\end{document}
I've used selinput instead of inputenc, because it's very nice even if you do not know the encoding of your editor.
pdflatex \documentclass{article} \title{<title>} \begin{document} \input{<document>} \end{document}. – Werner Nov 07 '11 at 01:58