You can buy that sort of kit off-the-shelf now, from HP and others. It's nothing exotic, it's basically your desktop PC on steroids.
NUMA is 90's tech from Sequent.
NUMA is 90's tech from Sequent.
The big HP NUMA boxes are Superdome and Superdome 2, and those have global memory access, though access to the local memory is faster than the remote memory; the requisite non-uniform memory access speeds.
Last I checked, the current Superdome and Superdome 2 series maxed out around two and four terabytes of physical memory.
If the current four terabyte maximum memory configurations and possibly the architectural 50-bit addressing aren't enough and you're willing and able to buy that much physical memory, then HP would probably interested in chatting with you.
No RHEL on Itanium, though.
From: http://www.theregister.co.uk/2010/04/21/redhat_rhel6_beta_1/