Do you already have SLC 5/05 talking to the panelviews?
I all your looking for is connectivity to the 5/04 processors, install a controllogix bridge. What this would consist of is a controllogix power supply, 4 slot rack, 1756-ENBT(ethernet card), and a 1756-DHRIO(DH+ card).
You can then get to all your processors on the DH+ network. With proper configuration, you can even message to the different processors thru the bridge. You cannot however download/upload to the panelviews. PanelBuilder 32 does not allow it.
This would be a less expensive solution than changing out all the processors.