x forward session with xdmcp

XDMCP allows logging into a remote host, but displaying the desktop on your own host.

1) edit /etc.gdm/custom.conf

[xdmcp]
Enable=true

[security]
DisallowTCP=false
AllowRemoteRoot=true

2) restart X (telinit 3; telinit 5)

3) login as root and run:

gdmsetup

4) On the remote tab, change 'style' to 'same as local'

5) On the security tab, tick 'allow local system administrator login' and 'allow local system administrator login'

6) restart X

To test, log off your host, and press F10 in the login GDM login window. You can enter the name of the remote host to login too here.