Here's a very simple mod you can do with a Fotopro Transformer tripod or sometimes called the Polaroid All Terrain tripod. Available in ugly chrome and Gunmetal Grey. When choosing, be aware that some packages don't come with all the pieces. It's probably found under several different names too, but basically it's a flexible tripod with swappable feet and uses the standard 1/4x20 thread.
Parts needed: 1) Flexible tripod with removable feet 2) (3pcs) 1.5" 1/4-20 bolts & (3pcs) 1/4-20 jam nut, 3) (3pcs) basic skate wheels and bearings. Could be Rollerblade or skateboard wheels. 4) About 30 seconds of time out of your day...
When unscrewing the feet from these tripods, they are on pretty firm. Don't worry, just wrench them off, they are indeed removable. The 1/4-20 bolt is not a perfect fit (a bit smaller), but it really doesn't matter once it's rolling. Just don't crank down the bearings too tight or the wheel won't move as freely. This particular tripod isn't built for huge cameras, but should do fine for cameras around 3lbs. For anything heavier, I still recommend at least the Pico Flex table Dolly.
Something like this is perfect for camera sizes like the Sony HX9V or GH2. Find these tripods on both eBay (click here)
I was testing this about a week ago, but finally published it to the public. Taking all the same little electronics from the JuicedLink DIY slider project (continuous servo, servo driver, and battery case) the little Pico Flex dolly is moving on it's own. The speed is variable and with the size of the pulley. It can go really slow, but what you see is the fastest setting it will go. A piece of scrap acrylic plastic and double sided tape was all that was used to mount it temporarily while I try to figure out the cheapest and best way to drive this thing.
A rubber band pulley system didn't do so well. The band would stretch and when there was enough tension built up, it would snap back causing a jerking motion. The direct drive was the simplest way to turn the Pico wheels and was much more consistent. Using this technique could apply to all existing Pico Flex Dollies without replacing any existing parts. The servo is extremely strong and since the Pico moves with little effort, it can move quite a bit of weight.
Another Clever Pico Flex Dolly Modification - Motorized + Lasers
YouTube Member dim3m has motorized the Pico Flex, and has also added lasers for an easy way to identify the rotating axis. This is a common practice used in those high end three wheel skater type dollies. By aligning the axles with the lasers, the cross path will be the center of rotation. This is where you need to focus your camera. Right now the lasers are just temporarily being held on with Friction arms as a proof of concept. [Thanks dim3m] You can find pen lasers fairly cheap these days in just about any store, but if you're lazy they can be found online for about $1.49 (click here)
YouTube member TheAussieInLA puts together his DIY version of the SpiderTrax rotational dolly and gets some pretty cool results. Looks like some basic skateboard trucks, skate wheels, and flat steel. [Thanks Alex]
The original version sold at PhotographyandCinema.com is no longer available, but if you're not the DIY type the next best version for the cheapest price is made through Konova. The Konova rotational dolly is well built with an anodized plating and a few fancy graphics. Although they opted to use roller blade type wheels, they flipped the axles upside down and shaved them flat, bringing it closer to the ground for low shots. You can find them following the link below.