Postgres vs. intel ccNUMA on Linux

Hackers,
Any tips / conventional wisdom regarding running postgres on large- 
ish memory ccNUMA intel machines, such as a 32G dual-quad-core,  
showing two NUMA nodes of 16G each? I expect each postgres backend's  
non-shared memory usage to remain nice and reasonably sized, hopefully  
staying within the confines of its processor's local memory region,  
but how will accesses to shared memory and / or buffer cache play out?  
Do people tune their backends via 'numactl' ?
Furthermore, if one had more than one database being served by the  
machine, would it be advisable to do this via multiple clusters  
instead of a single cluster, tweaking the processor affinity of each  
postmaster accordingly, trying to ensure each cluster's shared memory  
segments and buffer cache pools remain local for the resulting backends?

Thanks!
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James Robinson
Socialserve.com