Yes, Jerry is right--it would help to know what you have in mind...the scope of your project so to speak. I've done some light painting on a grand scale and a small scale--different tools for both.
This image was light painted with an LED panel (on low!) on a stand very far away...
Milky Way over the Moulton Barn by Nicole Fernley, on Flickr
And this little still life was light painted with a little LED flashlight with a little PVC pipe elbow taped to the end of it:
Memento Mori by Nicole Fernley, on Flickr
One thing to remember with light painting is that brighter is not always better because you are often doing long exposures. Often a little flicker of a flashlight will be sufficient, but as you experiment you will likely figure that out.
Another thing--whatever light source you choose, you will likely want to add some color filters to warm up the light a bit. That can be as easy as taping colored cellophane to your flashlight.
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