Just to follow-up, the following worked for me:

1- Install stock Fedora 17 (x86_64) on nodes
-- We do some basic puppet-based configuration such as LDAP auth for the machine, etc. but otherwise pretty plain server config.
2- Downgrade the kernel to 3.4.6-2 version (and make this the default)
3- Stop and disable NetworkManager service
4- Start and enable network service
5- (reboot)

When doing the remote install (from engine) of the vdsm stuff on this blank system, the network/bridge will *not* be automatically setup.  (I think it will be setup if you leave NetworkManager running, at least that was the experience last time.)  This worked out for the best, since it meant that my network didn't get broken this time.  I manually setup the ovirgmgmt bridge (which you must do or it will not activate the new server) and everything is happy (talking to NFS share, running VMs, etc.).

Lingering issues are minor:
- Not sure how to get connection (port) info for Spice client.  I kinda prefer VNC anyway, so that's not a big deal.
- Guest VMs appear to always prioritize PXE over hard disk even though that is the second option in startup order.  (I have not looked into this yet, since it's not a big deal.)

Thanks to the responses that urged me to continue in this direction.

Hans