This is a clarification and expansion upon some things in the rules and some interpretations thereof, for those who are interested in crafting things, or buying stuff that needs to be crafted.
When using a craft skill, you can usually be assisted by one other person using the Aid Another action, though in special circumstances it may be possible to be assisted by several individuals. (For instance, if crafting normal scale mail, you might essentially have several apprentices pumping out individual scales...while the master armorer assembles them, rejecting any scales which are not of sufficient craftsmanship, etc.)
A crafter can intentionally work harder, rushing a job or working longer hours or simply (due to superior skills) working more efficiently, than the normal pace. This is represented by a voluntary increase of the DC on the part of the crafter. Even a poorly skilled character can attempt to work beyond his normal limits, but of course if the check is too low, such an effort will result in loss of materials as well as wasted time. However, it is when a master craftsman works at his greatest efficiency that his expert skills can show the fastest results.
Reminder of the mechanic -- each week, the crafter makes a skill check, if => the DC, then (skill check x DC) silver pieces worth of progress are made towards the market price, and when the market price is exceeded, the item is completed. Thus if a crafter raises the DC and still makes a successful check, more progress is made during that week.
In Drakara, master craftsmen usually are able to gauge their own abilities fairly well, and can determine what rate of progress they are able to guarantee by 'taking 10', thus having no chance of ruining materials or wasting any time. Thus a master craftsman will generally set the DC of a particular task equal to the normal result of a 'take 10' with his skill, which may include a guaranteed level of assistance from an apprentice or associate.
For example, an armorer wishes to construct a masterwork chain shirt. The normal DC for the 100 gp chain shirt is 14 (10 + AC bonus), and the DC for the 150 gp masterwork component is 20. However, this armorer has one assistant who is guaranteed to be able to hit DC 10 with his own craft (armorsmithing) skill (2nd level expert with 5 ranks, +2 INT bonus and +2 for Skill Focus = +9, d20 = 1, +9 = 10, cannot fail). So the master armorer can count on a +2 bonus from his apprentice, and is himself a 6th level expert with 9 ranks, +2 for masterwork armorsmithing tools, +2 for INT bonus and +2 for Skill Focus, for a total modifier of (2+9+2+2+2=) +17, which means if he takes 10, his check result is a 27, therefore he sets the DC at 27 in order to finish the masterwork chain shirt as soon as possible in order to satisfy his samurai lord. The time required for him would thus be (250x10)/(27x27) = 2500/729 weeks, or ~3.43 weeks. (We'll let him get away with doing it in 3 weeks and 2 days, with the final finishing touches being put on the shirt in the early hours of the 3rd day of the 4th week, the day the samurai lord was told the shirt would be ready.) If someone stole his tools, then 2500/(25x25) = 4 weeks exactly...
Not all crafters are willing to stress themselves to get a job done in the minimum possible time -- they may simply do the minimum work necessary to keep making progress -- but most Drakaran craftsmen are proud of their skills and industriously apply them to the tasks at hand.
Note that adamantine and mithril DO both exist, and may be used to craft items, but the only source of such items near Marike is indeed a hermit living in the hills to the east, out past some nameless village... Also, although the cost of adamantine and mithril are greater than that of masterwork items, the actual difficulty of working it is no worse than that of doing masterwork quality (per the DM, items made from these materials are treated as masterwork for creation times). SO for such items, treat the material component costs as masterwork for the purpose of time to craft, but still must pay the appropriate monetary costs to use that type of material.
As far as weights etc. go, Pete noticed that there was an inconsistency... I am doing as follows -- for any item of mithril which is specifically in the items listed in the DMG, weight remains as described in the appropriate entry, i.e. a mithril chain shirt weighs only 10 lbs while a regular chain shirt weighs 25 lbs -- but for other mithril items not listed, weight is 'reduced by half', so a item normally weighing 15 lbs which is then crafted of mithril will weigh 8 lbs.