The one thing I didn’t get to work is ~/.xsession support.  Any ideas?

I’d real like to get that fixed and then we can finally replace SLiM
with GDM as the default.

BTW, at the Guix Days, there were discussions about defaulting to
LightDM instead of GDM.  I forgot to mention then that using LightDM
wouldn’t solve the GNOME use case; in particular, closing the lid under
GNOME wouldn’t lock the screen, and clicking the lock button wouldn’t
have any effect, which is pretty bad.

Ludo’.