Nested VMMs. Intel's 4th gen VMCS enabled chips.
This summary of VMCS suggests that we need Intel-VX, EPT and for any serious nested KVM work.
Here are some contenders:
$770 optiplex3020 i5-4570 DDR3 sdram (16GB max). 2 DIMMslots.
$370 barebones supermicro-5030A-iL DDR3-1600/PC3-12800 SDRAM (32G max), SATA600, lots of expansion potential
$890 Optiplex 9020 8GB, 1x550G SATA 7200 supports up to 32GB nonECC 1600 DDR3 SDRAM in 4 DIMM slots. Avoid the small form factor which only has half o this.
Dell xps 8700 comes with a 4thgen processor (VMCS, EPT, VX) 8GB DDR3 ram with expansion up to 32GB, a 500GB SATA 7200 drive with room for up to 3). $750
haswell xeon as described by wikipedia _might_ indicatet that the supermicro is ok.













