Months ago I gave to my sister a lightbox so she could make a nice gallery of her hand-made jewelry, but to make the lightbox works at the best she needs also two powerful light sources.
Two external flashes are of course perfect, but it's an expensive choice, and some radio transmitter are also needed to syncronize the flashes with the camera. A cheaper solution should be make yourself two lamps which fit your requests. Here it comes the instructable for this light set!

Step 1: The CFL Lamps

These lamps are 22 watts ~~neon~~ CFL lights (cold light, but you can buy both warm light, with right digital camera settings it's the same), they're powerful enough and have a wide surface which diffuses light and makes soft shadows. NEON lamps are not right for photography because their frequency could interfere with shutter speed.
You need a container for them. I've discovered that these two steel food bowls have the exact dimensions to keep them inside.

Step 2: The Stands

Then you need the supports for the lamps. These bookends are perfect for our purposes, they're stable and sturdy enough, with a wide base and also an hole in the right position.
You can add some silicone tips on the bottom surface for a better grip.

Step 3: The Sockets

I've used a lamp-holder which has two nuts and let you choose the right distance at which screw them. You can try also with a different model or color for your holder, cables and switch. I wasn't sure about the color so I've bought them all.
You can try to imagine how the project should be with the different color sets I've bought. If you choose the gold one be sure to have an additional cable of the same color to make connections, or buy two sets so to cut some cable from the second one.

Step 4: Draw the Holes...

My design provides to cut a round hole in middle of both bowls and bookends, so that we should use the lamp holder to keep them together. With the help of the plastic nut draw the circles of the right measure. Be sure to keep enough space for the bowls under the hole on the bookends.

Step 5: ...choose the Tools...

You can cut the holes with a little drill, as I did, but this is an hard and long process, and I suggest to find someone which lends you a specific tool, if you don't have it already.
You can avoid to cut holes in the bookends (whenever yours are the same as mine) buying some nuts and hollow bolts and using them to connect the lamp holder to the bookend's existing hole.

Step 6: ...and Cut Them!

When you've drilled the holes check that the lamp holder fits good. If not enlarge them with a file, or try with a drill with a grind, because the steel of the bowls is a very hard material.

Step 7: Assembling

Place side by side the bowl and the bookend and lock them between the two plastic nuts. Tight hard so it couldn't loose anymore. Try screwing the lamp inside the holder to see if it doesn't interfere with the bowl's surface. Maybe you want to turn the holder so that the lamp remains with the white arms in vertical or horizontal position.

Step 8: The Wire

Cut the wires at right length and solder the at the wire after the switch, so you can turn on both with the same switch. I decided that one of the two lamps should have a longer cable, so to keep the switch at one side of the table, but this is not always useful, so you've to make your choice.
When all connections are ready mount the backs of the holders and screw lamps again in position.

Step 9: Done!

As you can see the lamps are now ready to test.
I wished to make a better look to them, adding a white surface which should diffuse light better. Unfortunately I discovered that these CFL lights could not work in close locations, indeed one of them burned after some minutes. So, because it's too much hard with my tools cut some ventilation grid in the bowls, I should say that the additional diffuser is useless, especially if you'll use the lamps with a light-box.

Step 10: [optional] the Diffusers

Anyway I'll explain you how to make the diffusers in case you wish to use some LEDs lights instead of the CFL lamp.
You need a white, almost transparent, plastic sheet. I've used it times ago to build a ring-flash and it works well.
As elastic I've found that an hole bike wheel tube is very good.
Cut from the plastic sheet two circles about 2-3 inches larger than the bowls, then cut two stripes from the tube as long as they remain tight around the bowls. Connect the stripes extremities with some staples.

Step 11: Enjoy in Kitchen!

Now place a sheet on a cylindrical container with the same diameter of the bowls, and lock it with the elastic, the begin to glue the border of the diffuser. Finished all the perimeter, depending of the glue type, wait for some minutes, and then turn the elastic so that it makes contact with the sheet border. Repeat this process two other times folding the sheet around the elastic. Let it dry and dress up the lamps. The elastic should keep the diffuser stretched strongly. Your (LED) lamps are now ready!

Step 12: Test New Lamps!

It's time to test your new equipment. In my case I didn't use the lightbox, but I noticed they works great the same (anyway here they both have the diffuser mounted, it was instants before one lamp burned).

Step 13: Results

Here is a couple of fast photos I've shot as soon as I finished the project.
I'm sorry for the empty bottle, but I drank all the beer after the effort to drill the holes in the steel plates!