I'd be happy to make you one out of wood. I have some scraps of oak, walnut, cherry, maple, white ash, hickory, baltic birch plywood, and a number of mahogany look-alike's that I could make it out of, or I can get you the exotic wood of your choice (for more $). It'd have to be delivered after the first of the year, because I'm trying to finish up some Xmas presents this month, but I would be happy to make one for you if you aren't in a hurry.
Just give me the dimenions: length by width and the total height (off the desk). If you want it slanted front to back, let me know the total height off the desk at the front (closest to you) and at the back (next to the keyboard).
Easiest (and cheapest) way to construct it if you want slanted would be to add risers to the feet, but I could make it a solid block with a slanted top (and flat bottom) as well. I would put some small rubber feet on the bottom in any case.
Otherwise, a flat, sanded, finished piece of rectangular wood with the corners rounded and the edges all radius-ed would be a quick and inexpensive.
Any local woodworker could do the same for you. I'm in Denver, CO, so shipping would need figured in.
I'd guess I could make the simplest form for you from scrap lumber for $25. A slanted one with exotic lumber might run $40. As a one-off piece, these prices are actually losing money prices for me, but if we started talking about production level quantities, the price could come down. Just a thought. I think it would be fun.
If you are married to acrylic, though, I'd have to do some experimentation, but I might be able to replicate the ducky "bent acrylic" version.