high-end enterprise storage for servers. get some fibre channel storage arrays or one of these. but I haven't lived with any of these solutions - only some old RAID controllers built-into the server itself.

EMC² are rather large disk arrays - they bought up CLARiiON which used to be fridge-sized fibre-channel disk arrays years ago - I think they still are. EMC² has about 5 lines of disk-based storage in addition to archival, VMWare offerings, and other software.

it's a array of 9 RAID-5 removeable Flash SSD disks with DDR SDRAM cache. 6U high rack unit I think. The world's fastest storage. If you have a database you are running, get one of these! Uses SLC Flash which is better than most, has max 100,000writes/block, and under-reporting and wear-leveling is used to evenly distribute the writes, so a card will last for 3.25 years. The memory in a RAMSAN can be shared across multiple servers simultaneously. The RamSan does not need to be thrown out when you upgrade your server. RAMSAN is a more economical way to accumulate large memory capacities. Redundant-battery-backed DDR cache RAM with either hard disk or flash to backup to. If you can boot from SAN, you can boot from RANSAN.
This is for accelerating databases like Oracle and avoiding the expense of upgrading servers, RAM, & RAID (reducing costs) it is also for online transaction processing, data warehousing, file system metadata acceleration, database systems, non-linear video editing, software configuration and versioning tools acceleration and testing/benchmarking. Please see Solid State Disk Solutions for more ideas.
Windows, Linux (Red Hat, Suse), Solaris, HP-UX, AIX, IRIX, OpenVMS, HP Non-Stop, and Mac OS.

HP's StorageWorks looks pretty good.

requires a PC or server, but you can do a a fair amount with a PC and a full tower Armor Quad Fx case. 6 int. drive bays and a dual-proc AMD socket F workstation motherboard (ASUS L1N64-SLI WS/B), although a HW RAID card would give you speed. I know just the one (Excel spreadsheet) for low-end solution. per-network NFS tuning. enhanced CIFS options. Multiple NIC bonding. Advanced iSCSI setup. This can be an Enterprise cluster package if you want it to buy it that way. PLEASE read description. Turns an x86/64 system into a NAS/SAN appliance or IP storage gateway. Can be deployed as a virtual machine instance. Supports 10Gbps ethernet & Infiniband interconnects. Block level: iSCSI, Fibre channel. File-level: NFS, CIFS, HTTP/DAV, FTP, rsync. RAID 0,1,5,6,10 support.