OES2 and Virtualized NetWare really don't have anything to do with each other. Yes, Novell tells you that NetWare is virtualized with OES2, but it's more of a marketing spin. If you WANT Netware still, you can run it virtualized, but it's completely unnecessary.
When it comes to virtualization, NetWare 6.5 can be virtualized on many hypervisors. Older versions of NetWare can also be virtualized. You don't have to use OES2 to virtualize NetWare, in fact, it's not OES2 that does the virualization, it's actually SLES 10 SP1 that gives you the hypervisor. So you can virtualize NetWare on VMWare, SLES 10 SP1 (XEN), Virtual Iron, etc.
Additionally, running OES2 does not mean you are running NetWare, native or virtualized. You certainly do NOT need to run NetWare when you have OES2. OES2 is a package of services that run on SLES 10, and provide similar, but advanced services as what NetWare did: File system (NSS), Printing (IPRINT), DHCP/DNS (Integrated into eDirectory), iFolder, and more. In fact, you could migrate from NetWare to OES2 (full linux), and it can be done transparently to the end users with no disruption to network services, and no changes to the end users workstations. It's nothing like you would expect from a typical OS Migration. Try doing the same thing going from NetWare to Windows, or NetWare to Linux by itself, or Windows to Linux. You're going to be in for a bumpy ride.
We migrate people all the time and in most cases, nobody realizes that a change has been made, until they start seeing some of the new services they didn't have before.
One other thing to understand about the difference between NetWare and OES2.. While they do provide the same services, Many of the newer functions are only being developed for OES2 (running on Linux kernel). So you are actually holding yourself back by staying on NetWare. You cannot get iFolder 3 on NetWare, only on Linux. That's only one example, but theres changes in iPrint and other stuff too.
If you use ZENWorks, the new version ZCM 10, it doesn't even run on NetWare. You need either Linux or Windows to run it. That's the direction Novell is heading.
Hope that helps.