There are lots of great designs here, there, and everywhere for camera sliders. Whether this is better (doubtful) or worse (anything is possible) it was within my capabilities and so far, is doing what I ask of it well.
My goal is to add a 5rpm DC motor to drive a full length piece of all-thread to move the carriage for time lapses - but have not found any locally yet, so after I figure out the linkages eBay has a few to choose from and we'll give that a go.
The shopping list (save for the wheels) is a Home Depot/Lowes/Ace Hardware trip away, and approx. $15.00 of parts/pieces.
2 - U-Post fence posts (3')
1 - 1/4" All Thread (3')
1- 1/2" square steel tubing (3')
1 - Simpson T-Strap (6")
4 - 1/4" Cap Nuts
12 - 1/4" Washers
3 - Inline Skate Wheel Assemblies
(In the picture are some 3" x 1/4" bolts and coupling nuts, these are/were to make leveling legs but so far have not been needed)
UPDATE: The motorizing of the dolly is complete, the instructable for it is here: http://www.instructables.com/id/Yes-Another-Camera-Slider-NOW-MOTORIZED/