They occasionally do a dark brown color as well but I don't have an example of this. Check out their products page to see some of the colorations. http://www.cerameco.com/products.php

Like it has been mentioned earlier when new it looks obviously man made but after a couple months in the tank it looks great.

The rock is actually made in a variety of colors from dark brown to nearly white. It just depends on the mix they are making at the time and allows you to choose the background color of your piece. Most of it is made in the tan to light gray color.

This product is particularly well suited for a small tank because you can get an interesting free standing structure in a small package. It's really hard to stack rock in a pico because of the size constraints. 

Davser,

I have a piece that may work for your Pico. Here are a couple pics.

You can also look for other pieces at the aquarium, marine aquatics and I believe Fish 4 You has some as well. If you want something specific look at CeramEco's site in the products section. Pick out a basic shape that you like and then call them and tell them exactly how big you want the piece to be. It takes 2 to 3 weeks to get your piece made, depending on their production schedule, and every piece looks different so the on-line pics aren't exactly what your piece will look like. 

I don't recommend going down to the shop looking to score some VidaRock as they try not to keep the finished product in house. Orders are produced and shipped out so there is room to make more. 

I would recommend you contact them if you want a specific piece made and have the time to wait for it's production. As it has been mentioned before this is more of a factory and not a store.