@Bob - Thanks for the detailed account of your experiments! I am almost ready to release my tweaked design for the 90 degree bracket and top cover that uses the flexible USB cable as the rotation joint. The design includes a little clip feature that holds the serial adapter board securely inside the 90 degree bracket, and a pinch feature that secures the USB cable coming out of the scanner cover. We are doing a series of scan tests today to make sure the cables won't come loose and bind over time.
With regard to the extraneous points, your assumption is correct - that reducing the scan rate to 500Hz does reduce these. We are finding that these extraneous points are a result of low signal strength measurements. Things that affect signal strength are the scan rate (slower is better), ambient light conditions (less direct sunlight is better) and the surface characteristics of the environment (more diffuse and white is better).
I went ahead and made a screenshot of your scan because it's so awesome! By reducing the brightness of the lower signal strength points, you can clearly see what surfaces are visible to the scanner.
@ptegler - We have been playing around with the stepper motor driver settings, and this is one of the adjustments we are tuning. Of course pulling more current has other adverse effects, like shorter battery life and more heat generation. Hopefully we won't have to increase the torque with improvements to the cable arrangement.