Angry Badger has a rather extensive 15mm Barricade set available now over on their website. Go check it out.
From the update:
Angry Badger has released a 15mm-scaled version of their popular Barricade kit. The 15mm barricade set comes with (20) 2 inch modular walls, 1 entrance wall, 20 straight walkways, 4 corner pieces, 4 guard towers, 2 staircases, and one tank gate.