HPC has been doing this stuff for decades, it's a fairly well understood problem how to achieve "zero queuing".
It's worth mentioning that Infiniband is incredibly affordable for datacenter networking and has excellent tooling on both Linux and Windows these days.
Fibre Channel is about the last example of a circuit-switched network, and it's pretty much dying.
What really makes the big difference though is the presence of the subnet manager. Which pre-programs the routing information into each switch at fabric bring-up time. This is what causes Infiniband to act like a circuit switched network despite ofcourse being VCT at the PHY layer.
List prices alone are very attractive:
36-port QDR (40gbits) switch http://www.colfaxdirect.com/store/pc/viewPrd.asp?idproduct=1...
Dual port QDR HBA http://www.colfaxdirect.com/store/pc/viewPrd.asp?idproduct=1...
The cost benefits are compounding when you go up to FDR (56Gbits) and make use of RDMA aware protocols, like iSER, SRP or SMB3.