I am installing a new NetBSD/xen box (-current) and have a few
comments.

Thanks for all your work on this.

It would be nice if rc.d/xend would do the MAKEDEV operations if
/dev/xenevt is not present.  Or perhaps /dev/xenevt should be created
by a default install.  (I had to read the MESSAGE since xend silently
exited.)

Should xenkernel be ONLY_FOR_ARCH and/or ONLY_FOR_PLATFORM?  It seems
it should go in libdata, or share/x86_32 (not really share, but if
it's to be usable on any arch that would make sense).  Having
/usr/pkg/xen-kernel feels like namespace pollution.

It might be nice to have a metapackage that requires xenkernel20 and
xentools20 and grub.  xen20?  Perhaps this is unwarranted.

It might be nice to include a sample grub config file in the
xentools20 package, or a script to make one, check that xen and
netbsd-XEN0.gz are present, and run grub-install.

Here's mine in case anyone finds it useful:

# Grub config file for NetBSD/xen. Copy as /grub/menu.lst and run
# grub-install /dev/rwd0d (assuming your boot device is wd0).
default=2
fallback=0
# boot after 10s the default entry if the user didn't hit keyboard
timeout=10
# use vga
terminal console
# Load the NetBSD bootloader, letting it load the NetBSD/i386 kernel.
title NetBSD chain
  root        (hd0,0)
  chainloader +1
# Regular NetBSD - does not get boot options
title NetBSD
  root (hd0,a)
  kernel --type=netbsd /netbsd-GENERIC.gz
# Xen/NetBSD with 128 MB
title Xen 2.0 / NetBSD (hda0, vga)
  root(hd0,0)
  kernel (hd0,a)/xen.gz dom0_mem=131072
  module (hd0,a)/netbsd-XEN0.gz root=/dev/hda1 ro console=pc
title Xen 2.0 / NetBSD.ok (hda0, vga)
  root(hd0,0)
  kernel (hd0,a)/xen.gz dom0_mem=131072
  module (hd0,a)/netbsd-XEN0.ok.gz root=/dev/hda1 ro console=pc
## end of grub config file.