Help booting Xen under RHEL6 beta2

[Dan Magenheimer <dan.magenheimer@oracle.com>]

With RHEL6 beta 2 now available, I am once again trying
to get a fresh Xen 4.0-testing tree booted "underneath" it.
(This is for my Xen development machines, no political
comments please ;-)  I'm sure there are some similarities
between this process and the process under FC13(?);
any help appreciated.

I have cloned xen-4.0-testing.hg and successfully built
a full set of Xen "stuff" with "make world".  The dom0
kernel that is installed in /boot is vmlinuz-2.6.31.13
I used the default config (and default responses to
the "make oldconfig" that seems to be run by default)
to build this dom0 kernel.

1) Is there a better config file to start from for
   building the dom0 kernel?  For example, I see that
   CONFIG_SYSFS_DEPRECATED{,V2} are not set, and I
   am fairly confident that this kernel will not boot
   a RHEL6 environment without it.
2) What do I use to build the initrd?  The standard
   "mkinitrd initrd.img version" yields LOTS of error
   messages and, in any case, I believe that dracut
   should now be used instead of mkinitrd?
3) Should I be using a different/newer pvops kernel?
   IIRC, there is an issue with booting >=2.6.32
   pvops dom0 with pre-xen-unstable hypervisors? Or
   is that fixed in latest xen-4.0-testing?
4) Anything else I should watch out for?  E.g. recent
   tool changes due to udev or xencommon or ???

Most of these final steps are black magic to me and
I've been using a recipe on RHEL5uX for them for
so long, I'm not even sure what to look for if
(when) the dom0 boot fails... and trial and error
is not very productive for this kind of thing.

Thanks,
Dan