If you get photoshop, follow a couple of tutorials and use some brushes you might just have something here.
I can tell just from looking at these that you have potential, as some of the ideas behind them seem very sound, such as the second sig shows creativity with the integration of the render with the background by making it seem as one rather then just an image slapped onto a background.
If you need any help with getting photoshop, or any help from there after, I would be happy to help