===== Requirements =====
  * ruby interpreter
  * "fat tarball" of desired Xfce version

===== Install =====
This is the core of the installer.
<code>
svn co http://svn.xfce.org/svn/xfce/installit/branches/installer-single-file installit
cd installit
./autogen.sh
make
sudo make install
cd ..
</code>

===== Xfce Config =====
<code>
svn co http://svn.xfce.org/svn/xfce/xfce-installers/trunk/xfce44 xfce44-installer
cd xfce44-installer
</code>
Update the version number and whatever else you want in xfce44.xml, the configuration file for the installer.

===== Xfce Components =====
<code>
mkdir release
cd release
</code>
Acquire a fat tarball and place it here.
<code>
tar -xjf xfce-*-src.tar.bz2
</code>
That'll create a xfce-.../src directory containing a bunch of .tar.bz2's. Extract each of those and move the resulting subdirectory up to the current working directory, truncating the version number from its name.
(I have a script to automate this. -ongardie)
<code>
cd .. #back to xfce44-installer
</code>

===== Build It =====
<code>
make
./xfce4-*-installer.run --check
</code>