I personally do not think that this is a good idea for inclusion in Emacs. However it is a fairly simple task to implement this feature in Emacs lisp. I am attaching to this message a quick implementation of this feature I threw together in about an hour. I am not familiar with the Emacs package mechanism but I am certain that this could be converted to an Emacs package without too much work thus making it easier to install.
For now it can be installed by simply placing the file in a directory located somewhere in the load path and adding the line (require 'user-load-dir) to your either .emacs or site-start.el file.
Then from that point on, it will be possible to do exactly what you want, place a .el file in the directory specified by the user-load-dir variable (~/.emacs.d/load by default) and have it loaded without having to make any additional changes to your .emacs file.
user-load-dir.el