Tableau does not currently support a mechanism for multiple workbooks to share the same extract in some centralized location. Several customers have requested this feature for Server, so it is on our radar.
But let's take a step back to address your assertion that Tableau Data Engine extracts are the best approach for performance. If you have a fast database system, you should absolutely plan to take advantage of Tableau's ability to issue live queries to your centralized database. This "direct connect and go!" approach works very well for databases such as SQL Server. Do you find that direct connections do not give you the performance you desire?
I agree that it would be very useful to be able to store an extract in a centralized place where multiple users can access it. We are using SQL Server and the "direct connect and go!" option currently and the queries take a couple minutes a piece to load (each worksheet). Also, the cpu usage hits 100% or close to and that is just for one user. Any ideas on how to reduce the memory being used? (When we created an extract the worksheets load very quickly although the extract took 30 minutes to be created.) The data would need to be refreshed on a daily basis.