As for the IO stuff you mentioned...especially the SSD, how would you set that up? We need a lot of storage and also backup (using Time Machine). If I understand boot disks correctly, the OS and Apps would be installed on the SSD boot disk right...but what about the files you are actually working on? If they are on a slower disk, when opening, working on them, and saving, will you get a benefit from the SSD?
Don't get me wrong, SSD is no must, it sure does speed things up, though.
My suggestion (only suggestion, final assessment is totally up to you

) was two SSDs.
A medium sized one (80 to 120GB) for the OS and all your apps and libraries. That size should suffice, even for large libraries and cache files.
Then a second smallish (40GB) one where you keep the files you're currently working on (scratch). There is a variety of graphics users here that have this kind of setup and I've only heard positive feedback.
As for storage, I read from your posts that this will be a standalone machine, no servers, correct? In that case I'd use 2TB drives (they are cheap). Use one or two to store your data internally and external storage to back everything up.
The Mac Pro comes with a 1TB drive. I'd use that drive for a bootable clone of the OS drive and create another partition for a TimeMachine (versioned) backup of the scratch drive. That way you always have the machine up and running in case that either of the OS or scratch drive fails in a matter of minutes.
To backup the storage drives, I'd recommend an external enclosure with sufficient storage and use that with either TimeMachine or any form of rsync (rsync, CCC, SuperDuper).
Considering that the Mac Pro has only 5 internal ports for hard drives (plus one optical), that might actually be the only way to back up your data.
Edit: I just saw that the 3TB drives are actually quite cheap in the US. So you might not need an external solution for your primary backup after all.
1 OS SSD, 1 scratch SSD, 1 bootable backup (1TB), 1 3TB storage drive, 1 3TB backup drive.