What is the "thinnest" display manager available?

[Yuri]

I want to have as few packages installed as possible, and I want to use 
small window manager (dwm). But what is the thinnest display manager 
available? I know kdm and gdm both work, but both pull a ton of 
dependencies which I don't want.

Features required:
* automatic start (through /etc/rc.conf)
* automatically run xorg and window manager of choice
* automatically login a particular user
* not many or no dependencies

What is the smallest display manager that qualifies?

Or maybe there is an easy way to run xorg + WM with some simple shell 
script? Anything like this ready to use?

Yuri