The original SpiderTrax Dolly is no longer available via PhotographyAndCinema.com, but the Korean company Konova copied the design pretty much dead on. This would be the better alternative aside from making one on your own. Here's some friends working with the dolly during Valentine's day. They let the dolly control all the camera movements with no fluid head. Since there wouldn't be any panning involved during the motion, they mounted a simple Heavy Duty ball head normally used for photography.
By just using the wood flooring, table tops, counters, and other flat surfaces, they were able to achieve a variety of different movements you can't replicate with just a straight slider. For areas that might not be completely smooth, you can carry a roll of Heavy vinyl plastic (comes in rolls) found at any hardware or fabric store. This Vinyl material will even allow you to run on firm carpet. If you haven't had time to make one or if you're not rockin' a rotating dolly yet, this gives you an idea of how versatile it can be. It's an extremely inexpensive tool that can boost your entire video production with these unique movements. [Thanks Guys]