I was thinking it could be a prize at 250 posts or so. Something to bridge the rather wide gap between 100 posts and 500 posts.
Basically, the custom weapons would be based on a regular weapon, and would have a little extra kick than ordinary weapons. Nothing to drastic, just something to add more variety.
As this is still fairly early in the new story, I thought I'd mention it. For examples of how this might be implemented, look at Fighters for Freedom or Defenders of Azuraith. They seem to handle it well.
Personally, I like the idea of making a unique spell for Aaron after he gets more accomplished. On a side note, 250 might be too high I wonder how high the post count got last story... I don't think anyone made it to 1000.
Just some thoughts.
An adventuring scholar and Sage focusing on the study of Theoretical Spellcrafting.