Battery Box Compartment

[kinvodA]

I'd like to modify my battery box in the back of my '89 325i. I searched but didnt find much. I'm thinking about crafting something similar to the euro-battery boxes. I got a "practice" battery box at the junk yard last week so that I can do some trial and error

My primary concerns:

• Easy to remove the whole battery box altogether or just the upper level if i go that route
• Stable enough and big enough to hold a small bag with tools
• Looks clean (will probably carpet it)
• What kind of material to use, and how to mount to the existing battery box.

Any tips/tricks/pics are much appreciated.

Ryan A