Designing Hardware and memory for 40 Terabyte system

Hello,
Mostly we have tested our databases with 0.5 TB but we need to spec out a system for 40 TB. We don't have resources to do tests. How we can extraploate and what is the best practice and lookup places.
Till know recommendations are SQL Server 2005 Ent with data partition. We don't know how much memory, cpu or disks required for 40 TB system.
Thanks

Are you asking for specs to support 40 TB of drive space or 40 TB worth of databases?
If you're going to have 40 TB worth of drive space, then the storage sub-system you choose depends on what type of system these databases are going to support. Will it be OLTP or datawarehousing? If you're going to have high-transaction volume you're probably going to need SAN-based storage with fibre-channel drives. The more spindles the better. You may be able to get by with iSCSI if it's for reporting.
Server specs such as memory and CPU should probably be based off the number of users/transaction instead of the amount of drive space. I'd say that if you're planning on having 40 TB worth of databases, then you're going to have to get as much RAM and CPU's that you can afford.

It is OLTP system (inserts and searches). 40TB is drive space. We are expecting to have 1.2M min inserts to 3.6M records per day. 40TB is going to be the over the years ( 5 to 7 years). We did some tests on smaller systems, but we are looking good way to extraploate or some good articles where somebody designed already did large systems. Unfortunately we can't say to our customer more spindles and more memory.

You can build scalable solution which enables you to pay as you grow.
The key components : is the Enterprise SAN , which you can find upto 70TB , but sure very expensive.
As the technology change every 6 months , and life time of hardware and maintainance cost , and with new capabilities of data compression in sql server 2008 , build you solution within next 3 years with CPU , memory scalability for server.

We are in that process.