Here's a tip I've found very useful for tight work bench spaces.
Go to your local office supply store or computer supply store and check out the computer/printer storage/stand pieces.
Two particularly useful pieces are: 1. Computer Stand Keyboard trays and 2. Printer Stand/paper supply drawers.

The first one is a hard stand that is about 4" high about 24" wide and 10" deep. It has a drawer in it that pull out. It's designed to hold a computer/monitor on top and keyboard in the drawer. The way I have put it to use is to use the drawer for a tool drawer. You can layout all your 'flat' tools. I've layed out my rulers, pliers, nips, and tweezers all flat and easy to reach. Just pull out the drawer and there they are. The top is flat and acts as a nice work surface so you don't loose bench space.
There are keyboard drawers that easily mount to the bottom of a bench if space is really tight.

The second item is a basic box with drawers that is designed to hold papar in the drawers and a printer on top. Again the benefits are doubling up on space, flat work space on top. This item is great for taller items like paint and jars or bottle of micro sol, glue, etc.

These items are nice because they are solid, sturdy and serve multiple purposes.

Hope it helps

I found a tackle/tool box at Wal-Mart, about 14' wide, 10' tall and 6-8' deep. It has a storage area with lid on top and four divided draws in the front. I can store most of my tools in the drawers and larger items in the top. It fits under the storage shelf of old computer desk I work on. It is also great to take when I go to annual training, as I go to Ft. Benning, in garrison, not the field.

I like your idea. What else may be useful is one of those keyboard trays that attach under the desk and slides out for use. It could be use to store different items.