Actually, it is:

> The grant set forth in Section 2B(iii) above does not permit you to use the virtualized copies or instances of the Apple Software in connection with service bureau, time-sharing, terminal sharing or other similar types of services.

http://images.apple.com/legal/sla/docs/OSX109.pdf

In the same PDF, actually in the section 2B(iii) you are refering to:

"If you obtained a license for the Apple Software from the Mac App Store, (...) you are granted a (...) license (...) to install, use and run up to two (2) additional copies or instances of the Apple Software within virtual operating system environments (...)".

So "No OSX version allows for virtualizing it as a guest VM" looks like an incorrect statement to me. Instead, some OSX versions DO seem to allow for virtualizing as a guest VM, under some conditions.

Hmm, appears you are correct.

Previous versions just flat-out banned any sort of virtualization.

Appears this release now allows you to have up-to 2 OSX guests running ontop of an OSX host.

(A pathetic attempt at allowing virtualization imho, my Xen hosts at the office have 10-30 guests running concurrently per box)

Well, it's not completely unreasonable given that Apple is in the business of selling hardware. Of course they want you to buy macs. :)

In all my years, and colo'ed across 3 DC's... I have yet to see any OSX server hardware besides a mac mini...

There are a few companies that host Mac VPS instances, and the one I used back in 2011 was running on XServe's using what looked like a bare metal VMWare solution (Parallels had one too I believe). Rare even back then though, Mini's are definitely more common.

You don't even need it to be an OS X host, only Apple hardware. VMware allows you to install OS X on ESXi hosts that run on Mac mini or Mac Pro (but disables that functionality on all non-Apple hardware).