I have a couple of ‘core routers’ that I’ve combo’ed as switches as well…
They are 4u units each w/a pair of 4 port MT ethernet cards. Setup with VVRP protocol for failover.
Both of these units are generic PCs. These ones happen to be AMD powered 2.2Ghz cpus, w/actual IDE hard drives though IDE Flash modules would work just fine (I have a small ‘out area’ router is that configed - w/a IDE flash - works great).
Anyway the point is just about any ‘standard’ PC type unit will work, IDE is required (no SATA hard drive support as of yet). If you want failover then you’ll need two units.