The answer at the moment assuming you wish to build your own server with PC clients only (mac coming soon) use Windows 2008 server as we can change the quota for the size of virtual drives and simply install Quadrus software this gives you true project sharing and works properly. This has been used on a lot of big scale projects.
Can you please explain it little more. What is Quadrus software. We have win 2008 server and how will quadrus software enables Avid project sharing?