Garages and Carports - Novice Garage Shelving Questions

I've read through several of the "2x4 garage shelf" threads and still have a few questions.

I want to build a single shelf on two walls (form an 'L') above the workbench in my garage. We'll be storing various items in plastic bins and a bunch of computers.

Here's what I have:

a bunch of 8' 2x4's
3 sheets of 4' x 8' 3/4 plywood.

My plan so far:

build a 2' x 8' "box" out of the 2x4's. Fill this in with 2x4's ladder style ever 2'.

Fasten this to the wall using cabinet screws.

Cut the plywood down to 2' wide and fasten it to "ladder box" I just created.

Run a 2x4 down from the ceiling on each end of the 8' run to support the outside of the shelf. Use a shelf bracket in the center of each shelf (one on each wall).

Questions:
1. Any problems with this?
2. When I make the 2x4 frame does it matter if the short ends mount to the end of the 8' 2x4's or attach to the face like the rest.
3. I have some 2x4 hangers. Would it be stronger if I attached the inside 2x4's using the hangers? What about the outside 2x4's?
4. Any idea how much weight this would hold.
5. Where the two shelves come together should I bolt them together for added strength (one will go all the way into the corner, the other will butt up against the other shelf perpendicular to it).

Thanks in advance!