Fractal Design Define R6
Fractal Design Meshify S2
Phanteks Enthoo Pro
Phanteks Eclipse P600S
be quiet! Silent Base 801
All these have windowless versions available. Most will support 2x 240mm or larger.
If you are pricing out a workstation for a business, I recommend buying from a manufacturer like HP or Dell instead of building it yourself.
EDIT: Why did I make this my 1000th post? I've been here for fifteen fucking years.