Using bitmap image from tutorial How to create your own custom brush in Photoshop you can easily create your own vector brushes in few steps:
Simply place an image (download it here) in Illustrator and use live trace or Silhouette plug-in… you should get a grungy style vector brush like this one:
Choose one of the elements with select tool (use “V” – keyboard shortcut for selection tool), ((for instance, you can rotate it 90 degrees.))
Open the Brush palette (Window – Brushes) and choose New Brush option. Select the brush type, in this case – Art. Leave other options as they are and rename it. Save.
Voila – try it!