I have been surfing the web looking at some really impressive pallet projects. One of the ones I was most struck by was this pallet shed.
I think you'll notice one of the most striking features of the shed is the uniformity of pallets. It's important to note, pallets are not all the same. Finding and using the same kind of pallet, made by the same manufacturer and even those in the same production series is crucial to achieve this affect. You can sort pallets as you find them, or find a source of pallets that will provide with what you need.
For my own projects I've found a local filter supply store near my house that gets regular shipments from the same manufacturers. I noticed this place because there were always pallets outside, they always seemed to be new and clean, and they were fairly regular in size, shape and appearance. What I've discovered since then is that 1) the pallets were trash as far as the shop owner was concerned 2) the pallets were high quality, clean and pristine and 3) they weren't all the same, there are three kinds he gets regularly that are all nice and regular within their group. This means I have a regular source of quality pallets.
You can follow this link to learn more about the Tony Utterback Shed shown in the picture above.