Tested
------
SERVER
SYSLOG_HOST
SCREEN_01 thru SCREEN_12
MODULE_01 thru MODULE_10
CONSOLE_KEYMAP
XKBLAYOUT
NETWORK_COMPRESSION
XSERVER
X_HORZSYNC
X_VERTREFRESH
XKBMODEL
X_MODE_0 through X_MODE_2
USE_XFS

Implemented but untested
------------------------
SWAP_SERVER
DNS_SERVER
SEARCH_DOMAIN
XDM_SERVER
XF86CONFIG_FILE
XKBOPTIONS
XKBVARIANT
XKBRULES
XFS_SERVER
X_COLOR_DEPTH
X_MOUSE_DEVICE
X_MOUSE_PROTOCOL
X_MOUSE_EMULATE3BTN
TELNET_HOST

Not yet implemented
-------------------
NFS_SERVER
USE_NFS_SWAP
SWAPFILE_SIZE
RAMDISK_SIZE
RCFILE_01 thru RCFILE_10
SOUND
X_MODE_0 through X_MODE_2
X_MOUSE_RESOLUTION
X_BUTTONS
X_MOUSE_BAUD
USE_TOUCH
X_TOUCH_DEVICE
X_TOUCH_MINX
X_TOUCH_MAXX
X_TOUCH_MINY
X_TOUCH_MAXY
X_TOUCH_UNDELAY
X_TOUCH_RPTDELAY
LOCAL_APPS
NIS_DOMAIN
NIS_SERVER
XkbTypes
XkbCompat
XkbSymbols
PRINTER_*_DEVICE
PRINTER_*_TYPE
PRINTER_*_PORT
PRINTER_*_SPEED
PRINTER_*_FLOWCTRL
PRINTER_*_PARITY
PRINTER_*_DATABITS

Not applicable
--------------
NFS_SWAPDIR
LTSP_BASEDIR