I've seen this type of tile on the Home Improvement type shows. If I recall correctly, they are produced in sheets (like mosaic tile or listellos) with depth differences built in. If you look closely, you can see a repeating pattern every third row.
Creating this yourself sounds like a whole lot of frustrating work. If you're determined, a rectified tile would be your best bet.
Edited to add: Don't know where you got the pic, but perhaps you could backtrack to find a manufacturer?
BTW, not plugging it, but Norstone makes something similar in stone.
Last edited by Blondesense; 04-11-2011 at 02:30 PM.