O.K. this one goes to the designers out there!
I found a cool PSD for the Palm Pre released by teehan+lax. It’s an awesome PSD file that contains most of the common GUI elements that are available in webOS. You just only need either the Coconut font or the Avenir font. (Not included due to the license think).
These two fonts are found on your webOS device.
Most of the elements are built as vectors and so they are sizeable.
So start your Photoshop and create some awesomeness!