If I was in/near Irvine, I'd offer to help at a reduced rate just to play around with it. It would be a very interesting project!I'm sorry that I don't have time this month, or next, to spend a lot of time on this, because it's the kind of thing I would normally love to talk about at length. I'll see if I can pop in to answer anything that's not been answered sufficiently.
As for the OMG-way vdev... whoever did that needs to have their fingers broken. If you configured that, OP... well, all I can say is you REALLY need to spend some time reading these forums and most of the content in the "Resources" area. A 60-way vdev would be a horrendous idea for a typical system running gigabit... much less 40gig. It also makes me worry that you haven't done a lot of the other simple recommendations... like recording what serial number is on every drive (or you'll hate yourself when you have to replace a drive), configuring SMART testing and email alerting, pool scrubs, etc.
As for your pool configuration, I'd start with 10 6-disk RAIDZ2 vdevs. That'll give you a decent balance between performance, reliability, and capacity. I'm not sure you'll be able to saturate 40gig with that configuration, but it's where I'd start. That gets you 229.1TiB usable (accounting for the 80% rule, etc.)
On your Mellanox config... 20.20.20.20? Where did this IP come from? Unless you're working for CSC, you really should stick to non-routable IPs as a best practice.