How far did you get with your investigation into this? We're investigating thin clients and zero clients for a couple of scenarios. We're considering solutions from Citrix, VMWare and Microsoft to achieve this.
1) CAD users who have a full PC workstation here, but may periodically work from home. Idea being to give them a client to use at home that would connect through a VPN and remote desktop to their workstation here. The heavy lifting would still be done by their CAD class PC in the office. They could go home and pick up where they left off or work from home on a periodic basis with minimal hardware investment in the data center. Advantage to us is we're in control of what they are connecting with - who knows what is on their home PC and dictating they must have certain protection software on their home PC gets to be a sticky issue. Actual data all stays here, too.
2) Concept of actually replacing the full-blown CAD workstation for users who are occasionally in the software or for the college interns that come and go on a regular basis. Provide a them with a thin client connecting to appropriate hardware in the data center. Not sure cost would actually come down, but gains could be achieved in deployment time and flexibility.