At the moment, all tools are merchant bought, and cannot be crafted, as you know. For players to be able to create their own tools, a new skill tree would obviously have to be added. Aside from that obstacle, however, the idea would add even more complex diversity to Ryzom.
Here's what I think. All tools (pick, melee weapon crafting, ammo crafting, etc.) Would be bought from the crafter trainer with an appropriate amount of skill points. Nothing would be different about crafting these than other crafted items--they would still require certain materials and such. Unfortunately, this would mean Nevrax would have to impliment new uses for materials. Before you say "Well, a pick could be created from a point and a shaft!" think about this. Take some bark for instance. It can be used for ammo bullet or shaft. These uses have specific statistics for them. If one more use was added to bark, such as tool handle, this would have statistics for it as well.
These material statistics could be standard things like lightness, speed, and durability, and tool specific things like efficiency or control. So, a pick with a high efficiency statistic would be able to pull more material per second, where a pick with high control would decrease the rate of depletion for either the explosion bar or even the material deposit. Or, for a crafting tool with speed and durablility would let the user make items faster, and the tool would last longer. A tool with high efficiency and control would allow the user to make items with less mats, or allow for fewer degrades at the cost of durability and speed.
*note--there would also be medium and high quality patterns for coolness

Lastly, the quality of the tool allowed to use could be tied to will. For instance, a person with a will of 90 would be able to use a q100 tool. The higher quality the tool, the better its stats, just like weapons and armor.
This concludes the submission of this episode of random44's wierd ideas. How do you like it?