I just made a set of fun Photoshop steampunk brushes. They are made from clock parts and they have a photographic quality to them. The collection includes a range of gears and some funky metal bits too. They are sized upwards of 600 pixels and some are as large as 2400 pixels.
They are free brushes for personal use and an inexpensive commercial license is available.
You can download them from projectwoman.com.