Xdmphoto is a "user photo aware" clone of xdm. It offers essentially the same advanced functionalities as kdm and gdm, but only requires the standard X11 libraries and the Xpm library. In combination with xdmopt, xdmphoto allows you to select the window manager, color depth, halt and reboot, mouse config, etc. at the xdm login.
Is possible to have an ebuild of this, maybe in the portage tree? :)
Last update on Freshmeat is from 09-Aug-2000 - no website listed for it only the FTP site to download from, and a Google for "xdmphoto" didn't bring back any useful results to see if upstream is still alive.
CANTFIX wrt the above.