Some 256x256 icons I made from the following weapon packs created by Clint Belanger and p0ss :

• http://opengameart.org/content/kingdom-weapon-set
• http://opengameart.org/content/undead-weapon-set-and-weapon-rack
• http://opengameart.org/content/wooden-weapon-training-set

These icons can be resized down to 32x32 px.

To create each icon, I did the following with gimp:

1. Rotate the rendered weapon
2. Select by color (with a 0.0 treshold) -> click on grey outside the weapon
3. Suppr, then invert selection (ctrl i)
4. Selection -> grow -> 10 px
5. Create a new layer, put it in the backgroud, fill with yellow
6. Gaussian blur (10px) + 50% transparancy for this layer
7. Create a third layer, put it in the background and fill it with black