For proper operation and failover you must have a switch. All the Dell docs list that as a requirement. Going direct means one port on one CM and one port on the other. So no MPIO during normal operations. Also switches provide buffering for when server ports fill up.
You don't have enough ports for both the array and servers. So you're looking at something like a Dell 8xxx series switch. really no "cheap" 10GbE switches for iSCSI.
If the load isn't going to be too high, you could put the arrays on the 10GbE ports of the 4605 and the servers on GbE. if these are backup or video servers the sustained reads could lead to retransmits poor performance. A lot depends on the Supervisor Engine and Line cards on the 4506.
Re:6510 drives. There should be 48 drives not 38, is that a typo?
Is this going to be production data? Make sure you are using RAID6 for maximum redundancy.
I suspect the EQL firmware is old too.