Dennis Wunderlin does that. (He's already shot more than 300 videos for various Giz Wiz appearances!) And I know you're asking: "What's b-roll?" That's the video we use on World News Now when the gadget we're talking about has a demo that can't take place in the studio. For example we needed b-roll when we field-tested the Fugoo Waterproof Bluetooth Speaker. I dropped it in the Hudson River as the engine on my boat ran at full bore making waves, while Dennis shot the video of it still playing! (More info is at www.fugoo.com)
Dennis also shoots all the videos for The Giz Wiz Show on TWiT. (This Week in Tech.) Although his videos are downloaded via iTunes over 20,000 times a week as part of my Giz Wiz show on TWiT, we also put a few a on YouTube as a stand alone videos. We recently added a green screen to our recording abilities at Gizneyland Studios, but if you want to own a green screen, here's a fun video of a device we found at Pepcom, the Jakks Pacific Selfie Booth! It has it's own built in green screen so you can be 'anywhere' digitally! You can find the Selife Booth at Target. Adult size is about $60 and a smaller kid's version is in th $30-$35 range.
Giz Wiz Video: http://youtu.be/Wigp6XOlrpk
And I have my own YouTube Channel with hundreds of Dennis' Videos: