What would you define as a "commodity cluster"? To me it's a 512-core vendor-specific blade server with special interfaces to get more bandwith at lower latency across longer links. But maybe i'm just an old fogey.
blades were never more than a marketing trick: the offer nothing that can't be achieved in a standard chassis. there were a few multi-chassis SMP/NUMA machines that had cache coherency over external interfaces, but that was neither commodity nor HPC.