From my work in HPC, network storage is a common bottle neck.
Theoretical fastest storage
The absolute fastest hard drives, are actually RAM disks. It is possible to achieve 5GBs using consumer hardware. Though you will be limited to a few dozen gigs of storage at most.
Actual fastest storage
The fastest devices right now are NAND storage devices. You don't want to mention brands, but I am going to mention one anyway.
Check out the Fusion-io ioDrive. NAND storage devices can reach 2GBs.
High Performance Computing
Ram disks, and NAND disk are great for being fast, but they have very limited capacity for HPC. A much more common solution is to use a premade SAN running on SSD
I know you aren't looking for brands, but if you look at what all the experts in HPC are using, you can see the different technologies.