General Knoppix support for those who've read the FAQ at the Wiki
DELL PowerEdge R730XD Server 2x E5-2697v4 2.3GHz =36 Cores 64GB H730 4xRJ45
$407.00
Dell PowerEdge R420 Dual Intel Xeon E5-2440 v2 @1.90GHz 32GB RAM No HDD H710
$74.50
Dell PowerEdge R630 Server 2x E5-2650v3 2.30Ghz 20-Core 96GB 2x 300GB H330
$240.10
Dell PowerEdge R620 Server 2x E5-2660 v2 2.2GHz 20 Cores 256GB RAM 1x 480GB SSD
$139.99
Dell PowerEdge R620 Server - 256GB RAM, 2x8cCPU, 120Gb SSD/3x900Gb SAS, Proxmox
$320.00
R630 DELL 8 x 2.5'' POWEREDGE 2X E5-2680V4 32GB RAM IDRAC ENT & NDC 2X 495W PSU
$172.95
Dell Poweredge R730xd LFF 14-Bay 2U Server | Choose Your CPU & RAM Config
$477.99
Dell Poweredge R720 2x Xeon E5-2670 v2 2.5GHz 20-Cores / 128gb / 600gb / H710
$249.99
Dell Poweredge R630 2x Xeon E5-2680 v3 2.5ghz 24-Cores / 128gb / H730 / iDracEnt
$319.99
DELL PowerEdge R430 8SFF 2x E5-2640v3 2.6GHz =16 Cores 32GB H730 4xRJ45
$208.00