I did one with the smokin-it casters, but decided to get bigger ones at HF. Rolls over the cracks easier on my wood deck. The one I did with the wheels gets moved from a deck to a back storage shed across a lawn.
I just used washers to reinforce the top where I drilled holes to bolt the top down. The SI uses metric threads for the casters. I just took the casters into the bolt store and asked them to match it.
I built a frame out of aluminum angle for the base, the cabinets weren't strong enough to support the weight on their own.