I think that shared transients can be shared accross multiple nodes. Can anyone confirm this?
No, shared transients cannot be shared across nodes.
Are you sure that you're not confusing multiple nodes with multiple processes in the same node? Have you tried running two copies of your application in separate *machines* and verifying that you can share a file between them? If you can, then I suspect that although you may initially be reading the file into a shared transient, you've achieved the sharing using one of the approaches described by Krull (in which case the shared transient would seem redundant).
Dean.