The Hevi is a 420mm 7" hex, and it's a work in progress.
The arms are 8mm thick, the top and middle plates are 2.5mm, and the bottom plate is 3mm.
You can use Ichabod Jr's cam mount if you want to run a Hero. Or you can improvise a mount for a bigger HD cam, it can carry another kg easily on 5s. Some parts are here.
Here's a quick video of me flying it with a GoPro trying to induce vibes with a Reelsteady Go compliant cam mount.
And here's a quick snippet of Fincky flying a Black Magic 6k with it.
This frame is a work in progress, but I expect few changes to the carbon parts (two possible changes are the addition of 1/4-20 mounting holes further back on the top plate, and the addition of battery strap slots to the bottom plate). Most changes will be the addition of 3d printed parts, particularly a big HD cam mounting solution.
Kits with printed parts will include motor soft mount/armguards. DJI versions will include an air unit holder.
20mm standoffs will be included unless otherwise specified. There are 4 (!) spots for 30.5x30.5 stacks so you shouldn't need a whole lot of stack height.
Given that this is a work in progress, feel free to contact me at andyshen at mac dot com to discuss custom options.