From their announcement:
I'm now offering the Photoshop working files for selected models in my collection. These PSD packs contain all of the texture layers found in my PDFs, so if you're a Photoshop user (or Pixelmator on Mac) there's no easier way to kitbash your own unique designs.
New models are in the works, and I'll be releasing each new set in two separate versions: PDFs and PSDs.
I'm also running a sale at DriveThruRPG, RPGNow and Wargame Vault. Until the end of November, you'll save 20% off PDF model sets.