Hi Stefan.
I’m no expert.
The more questions you’ll be required to answer, the more solid it will be as a plan and as a solution.
For evey component of your workflow:
What is the OS/SW comonly used/needed storage capacity/Performance needs? Which components transfer data to other components and how?
This will get you to define what you really need from the solution in terms of: Aggregated performance, capacty, protocols, functionality, stability, $ and their priority.
Loved your diagram though it somewhat confused me :p.
Yuval
p.s.
I know a UK TV station that sounds similiar. They use Omneon as well but use it over NAS which they used directly with other clietns. I can try and get you a technical contact if you’re interested and he approves of course.