cement tile planter

i found instructions for making a cement planter with tiles set into it at http://www.thegardenartforum.com/sb/index.php?mod=content&id=89&hid=30&itemid=
this is beautiful and i tried something similar last night but this method is much better. i have alot of random rocks that i have habitually collected over the years. it would be a great way to find a use for them to set them into a concrete planter. i have many ideas for bonsai projects and i just cant find the right pots but i could make my own decorative pots with concrete and all the rocks i have laying around. i need long low planters that will fit on the window sill. i'd like to do some landscape type bonsai plant displays. i have tonnes of petrified alligator scutes that i get from a place on the river. it would look awsome to have a planter completely covered with the black dimpled scutes.