I've thanked John Quinn in a PM but I would like to thank him again publicly. The article he took the time to write about constructing a cement slab was all the inspiration I needed.
The
article is on the IBC site.
So far I have built 2 slabs and it's relatively easy and fun. I say relatively because I'm a long ways from perfecting what I'm envisioning as possible. My first slab, made a week ago, came out too heavy, too brown, too thick and according to my wife with too much resemblance to a cow plop. So much for being creative.

The second one I did today and although it's true color won't be revealed until sometime tomorrow, I'm very pleased with the overall look so far. Much thinner! Hopefully it is strong enough.
This slab might be used this spring! I have an order with Bill Valavanis for 15 Dawn Redwoods to be delivered in April.
Anyways, If you have been thinking of trying this I would highly recommend it.
The wooden dowels are still in the cement (drainage/anchoring) on the charcoal slab and will not be removed for several more days. Both slabs are roughly 28" x 13".
P.S. I have invested approximately $59.00 (US) in supplies for 5 and maybe 6 slabs.