It has finally arrived. 
 
Signature GPU Block - Kingpin 3090 - Optimus Water Cooling (optimuspc.com)
 
Pretty wild tbh

I just ordered mines tonight as soon as I saw the post here about it being available to order.  I don't know how many people got in before me, but atleast they took my order and money so that could be a good sign.  It does look wild, but the back plate waterblock is crazy.  It looks like it would cool better than some of the other front side water blocks.  I'm just trying to figure out from the photos how we are going to utilize the ports now there is a front and rear water cooling channels.  It might force me to make a change to my loop order.  But the clock is not ticking for it's arrival.  

We knew it was going to be expensive. I figure at least two months (if not longer) before it arrives, which means I'll continue on with my custom block work while I'm waiting:

 
 

The price came back to what Optimus shared it would be.  Considering the active cooling on the back plate, it is well worth it all considering.  The way it looks like thy designed the backplate, it really is like getting two water blocks instead of one.  Atleast we know its coming and about when, I feel better about my Kingpin knowing what is now coming.  Anything could have happened on Optimus' side to cancel or delay further the release.  Now it's like counting the days when we were waiting on the Kingpins knowing we were getting close.  

That thing looks absolutely incredible, what a beast. Kudos to Optimus.... wow.

Wow! Nice! I wonder how heavy it is. Look forward to temp reports once people start getting them.

Got my order in as well just now.
 
My only concern is that the active backplate looks to be thicker than the passive OEM one I have now.  The OEM one just barely clears the RAM sockets on my Asus Rog X770 Crosshair VIII Formula.  That said, from the pictures I see, the acrylic on the back does fortunately not extend all the way down to the PCIe connector, so hopefully it will clear.
 
I started out with the 3998 Hybrid KP, then I got the 1999 HC Kit and now the Optimus.  This sure is adding up to one expensive GPU!

 
Wow that's HUGE. Amazing. Gotta be at least 5lb with the rear block - I'd suggest vertical mounting. Unfortunately it's unlikely I'll ever get my hands on a 3090 KingPin, but it's nice to dream. :)
 
 

Looking forward to see the comparison with HC block. Going to need a good gpu support .

Just ordered mine.  Really pricey...over $800 Canadian, including shipping.  Thank you @Gotspeed for the heads up/PM.  Much appreciated.