Not a great picture, but what do you think? My hand is holding back the Accessory Relay (sorry) but its tight in there.
Tilt the picture to the right 90 deg, then the bottom block (bottom in the picture below not after its rotated 90 deg) is just in front of the passenger door hing area.
This is laying with my head towards the front of the car (in the passenger area under the dash) and looking up.
These are held on with industrial strength velcro.

As part of my DD NAV install next weekend, I decided to run two new fused & grounded distribution blocks up in the void beside the HVAC blower.
Each has 6 fused individual circuits you can power up.

One for 12 V constant power.
One for 12 V accessory.

Each distribution block has a new 12 ga 20amp fused power wire and dedicated 12 ga ground wires to and from the batteries.
12 V accessory dist block is tied in with a 30 amp relay, control for the relay is from Fuse 22 in the passenger fuse box.

12 gauge main power wiring should give me about 35 amps available power for either block right now.

Now all my Nav modules are plug and play into the blocks and fused and grounded.
I also will be connecting up the radar detector smartcord (run up to the mirror area).

Also future expansion for heated seat power if I need it or anything else that needs either available circuits.
If I need to upgrade the amps (first upgrade main fuses from 20 amps to 30'ish amps), all I have to do is upgrade the main wiring back to the battery (beyond 35 amps) and in the accessory case - the main relay circuit.
It was a lot of work, but I think its clean and ready to go.

Nav, IPOD and camera modules will go under the passenger seat for now (that's next).

Sorry, I am so happy with this and the wife has no idea (or cares) what it takes to make this happen in the cramped confines of the Vette.