Quick mention of the Salvage/Mastercraft/Technosavant/Engineer thing. In place of XP, I'm planning to use GoRM. Grams of Rare Material. It's a 1:1 ratio, 1 GoRM in place of 1 XP. Failure on the craft check will destroy an amount of GoRM depending on how much you missed the DC by. On occasion, specific GoRM (SGoRM) will be found. It's worth twice as much as normal, but only for a specific application. (Weapon, Vehicle, Armor, etc.) GoRM will be a part of loot.
Salvage will provide a means of attaining additional GoRM (I have to figure out the rate, still). It will also double the chances of finding SGoRM.
I love saying SGoRM.