Typically, reptiles are kept in rubbermaid bins for ease of cleaning. I have some difficult feeders who are sensitive to vibrations. When I try to secure the lid using tanks or akward cages, it often disturbs the animal and they drop the food. Using bins, I find that I can secure the lid easier and more smoothly. Space is the other issue. When you've got hundreds of snakes, the logistics of using glass aquariums just becomes rediculous. You can often times house double the amount of snakes in the same amt of space (at least!).
The system of rubbermaid bins are usually used when large colonies of snakes are kept. Custom made shelves are built so that the bin can slide in and out easily. When building them, lay the rubbermaid bin between two sheets of melnamine (sp?) or MDF. Put a spacer in there along with the rubbermaid bin. I like using 1/8 inch pegboard, but this can even get a little tight. For venomous, do all of this with the lid on. If anyone reading this wanted these cages for nonvenomous, having the top of the shelf act as the lid works well. Simply drill on the sides and you're all set. Of course, remove the spacer when the shelf is done. Before the animal goes in, add very small air holes all the way around. The size of the air holes depends on the snake species going in there. They can be melted or carefully drilled (which I prefer personally). I feel more comfortable with bigger holes for nonvenomous. Using the lid will be necessary or at least advised for your own health. You can safely remove the bin and set it on the floor before actually opening it. The only facility I've been to where this is used for hots was The Serpent's Den in PA. The system seemed to work very well for them. Flex watt heat tape is often put on the bottom of the shelves. In fact, you probably want that on the shelf before you drill the sides. I didn't do that when I made shelves for nonvenomous and the space got a little tight. Obviously, use a dimmer so the tape doesn't get too hot.
I think this system can be used safely, but I think it is a little more casual than keeping venomous should be, especially for the beginner. I would probably not recomend using this rubbermaid bin system for you. First off is experience. From your post, it sounds like this is the first cobra you're getting (aside from the one death). It is much easier to get ANY snake into a tall sided glass aquarium (or even better, a well designed hot cage like vision, etc) than into a short sided rubbermaid bin. The fact that the animal in question will be venomous makes this much more dangerous for you. I've never tried to get a cobra into a rubbermaid bin and put a lid on it, but I've gotten them into hot boxes. I know they can be slippery and quick when they want to be. This will be a challenge for you at times.
If you have a huge number of animals, it may be worth it for you to build a shelf system (especially once you gain more experience with this cobra). Housing any snake in a rubbermaid bin alone is too risky for me, especially for venomous. The lids are just too flimsy and can be bent. Without something flat on top, like the MDF, the possibility for escape is there. I didn't feel comfortable housing sand boas in free standing rubbermaid bins and I would never do it for hots.
For the record, I don't like housing in glass aquariums either. I think you'd be much better off getting a professional cage specifically designed for venomous, like vision. Every cage design has potential flaws, but I think most of these are the safest for the handler and for keeping the snake inside.
Other people may disagree, but I think that with your current experience and setup, avoiding a rubbermaid shelf unit would be the best for you at this time.
Later,
Dave
