If you want to run Solaris is gonna have to Sun (or Dell) hardware since Oracle no longer sells Solaris 10 licenses/support contracts for generic hardware.
Sun Fire X4450 (2U) + Sun J4400 JBOD (6U).
- 2U Quad Socket, Six Core Xeon 7400 Series (24 Cores)
- 8 x 2.5in Drives (x4450) + 24 x 3.5 Drives (J4400)
- 32 DIMM slots, Max 256GB RAM
- 4 port GigE, 2 PCIe x8 & 4 PCIe x4 slots
But if 24cores/drives in 8U is overkill for your needs, sun makes an 8 core, 16 drive, 2U Server (Sun Fire X4270), but only with 2.5inch drives. Since data loss is acceptable, run 2 striped drives per core to make up for the fact that 2.5inch disks only go up to 500GB a piece.
- Dual Socket, Quad Core Xeon 5500 Series
- 8TB Max: 16 x 2.5in SAS or SATA drives
- 18 DIMM slots, Max 144GB RAM
- 4 port GigE, 6 PCIe x8 slots
I don't know what your requirements are, but if you're willing to step away from the 1 spindle 1 core mindset you should evaluate an SSD equipped Sun 7310/7410 unified storage box. It would probably meet your IO needs for multiple 8-12 core frontends and scales up to six J4400 JOBDs with commodity 1TB SATA disks.