implementing a crafting type of system is definitely possible, but obviously requires a lot of planning and 'back end' design.
this is something that the optionsfile system is perfectly suited for:
- each raw 'resource' in the game has an options file specifying things like weight, value etc
- each 'product' (craftable item) has an options file that dictates what pre-requisites the object has in order to be craft, as well as perhaps details such as how long it will take to craft the item etc.
in
Fallen Earth (the mmo that i've recently become horribly addicted to) there are also tiers of crafting - so to make a gun or vehicle, you must first craft the individual parts of the object prior to crafting the final 'end result', which is basically the same as above.
in addition, in order to craft objects, you must have a specific skill level and the required 'knowledge' to craft the item (recipe in FE terms), which can be bought / acquired - but in order to raise your skill level you have to craft lower-level items, etc.
all in all, definitely do-able but would involve a LOT of paper-design work to keep track of everything. of course, if you want it to be online-based, you would do most of the crafting logic on the server etc but that adds a whole other set of management / design issues ;}