Spider Farming
Well, using non-maimed spiders, you could go with the "captive" (caged) version, or some other "spell" version (
Speak with Vermin). In the caged version, you set up cages, say 30x30' square and little taller than the spider. The cages have one door, to which can be attached a feeding/transport cage. When the spider has filled the cage with silk, you fill its feeding/transport cage with insects, attach it to the door, open the door, and let it in to feed. You then shut the transport cage's door, move it out of the way while the spider feeds on the insects, and gather the silk from the main cage.
With normal spiders, you need mesh netting. With tarantula-sized spiders, you need chicken wire. With giant spiders, you need steel-barred cages. The spider-farmers also need to be insect-raisers, to feed them (and giant insects, if giant spiders).
Keeping one spider to a cage is fine, as long as the cages aren't too close together. Assuming the spiders aren't too big, you could stack several cages on top of each other.
In the "Free Range" method, the Elves would promote a natural ecology, keeping conditions optimized for insects, and the spiders who love them... Periodic uses of
Repel Vermin could be used when going to collect the silk (and both Rangers and Druids have it... in 3e, anyway).
Sometime back in the 1960s, I recall seeing a comic book (Flash Gordon?) where some guy was asked by a friend to help him gather "tarel". He agreed, even though he didn't know what it was. He asked where they'd find it, beyond the giant spider-webs? His friend replied that the giant spider-webs WERE tarel! Naturally, the friend died in the collection, and our hero slew the giant spider.
If you do decide to use giant spiders, though, "super-rope" could be made from their strands. Silk has other uses besides clothing. Intelligent, communal spiders might be willing to spin extra silk as a "cash crop" to trade for giant insects. Besides giant spiders, however, there are also the intelligent Aranea spider-people (worshippers of Lolth), the already-mentioned Driders, and the nasty little Ettercaps, all of whom also spin silk.
Do you see any methods here that you like?
