Even standard 2x4 stud walls can carry an amazing amount of weight (just think hardwood kitchen cabinets filled with dishes, canned goods, etc.)
God is in the fasteners. If I wanted to (or had to) support everything off the wall, and do it for a reasonable cost, I would most likely go with industrial strength slotted wall standards (like they use in warehouses -- paint or powder coat to wife's specifications) of whatever height, attached (vertically of course ;~) to every other stud with 2" lag bolts every 12".
Use the same manufacturer's shelf brackets, 18" or 20" long and laminated 1.25" thick butcher block or similar for shelves. Position the shelves 3" out from the walls to allow room for wires and ICs. Drill a 1/4" hole in the bottom of the shelf where the retainer button (usually catches the edge of a narrower shelf) on the end of the bracket hits the underside of the (larger) shelf. This keeps the shelf from slipping around and keeps the brackets from shifting sideways.
I've not done this in my house, but have for clients.