More details are required, the term "workstation" goes a long way these days. Factors such as motherboard size are quite important as workstation class boards come as small as microatx that accept xeons/opterons, standard ATX, extended ATX, and SSI EEB standards require larger cases, where as you can even build a modern single use workstation out of mini itx components. One size does not fit all.
The type of workstation is also quite important as in some cases you will want to allow users to have large controller cards such as raid cards, ethernet cards, external hard drive controllers, large video cards, any number of add in cards will require a case designed to allow such cards within the system without blocking access to hard drive racks or system expansion. Another factor in configuration would also be for duplicators/data dumps where large number of 5¼ inch bays are required, most standard cases will have 4-7 and some will have 10-18. This is not to mention case cooling options as some components require very efficient cooling to keep temperatures and noise levels down. One of the reasons people like to purchase a workstation in a "normal" case type would be to avoid expensive rack mount systems and the use of small loud fans.
Letting us know what your expecting to house within these systems would allow people to make suggestions based on their own usage scenarios and allow you to get the input your looking for.
I for one have a requirement for mass storage, and finding a case to house 24x hard drives was not an easy task. Lian LI proved to be the company of choice for a few builds as their quality is unmatched in my experience. My latest has been the Lian LI PC343B Modular cube case, found
HERE for $350. Not cheap by any means, but offers probably the most cooling and expansion options. Using 5¼ bay converters to turn 3 bays into a mount for 1x 120mm fan and 4x hard drives allows me to fit the front of the case with up to 24 hard drives cooled via 6x 120mm fans, and internally I still have room for a single processor/dual processor configuration and use of some rather large controller cards. Fully stacked with hard drives I cannot use the longest of todays cards, but I would still have room to utilize any number of todays in demand parts and configurations.
Not using the bottom bay on the motherboards side however, will allow me to use just about any retail add in card as I have ample room without the bottom bay converter. The case also features a mount or using dual power supplies or a redundant system to allow maximum stability, being that these are mounted on the other side of the case (motherboard on one side, power supplies on the other) allows for easy cable management as well