Unless this changed from the last beta to live this isn't entirely correct.
this is for ALL classes. (yes that is a change that occured after the major stress test beta weekend)
as I haven't gotten to my crew skills yet in live I'm leaving this with the disclaimer : this was the way it was at end of beta and may not still be true.
Artifice makes: Hilts, Crystals (not just color but stats as well), Upgrade Packages aka Mods (upgrades Weapons & Armor), Shield Generators, and Lightsabers.
Cybertech makes: Upgrade Packages aka Mods (some work on both armor and weapons but not all), Droid armor upgrades, Teleporters, Ship Upgrades, Ear implants(The only crew skill that upgrades this slot) Grenades, and speeder bikes.
From what I've seen there are no Barrels in Cybertech. It seems to me to work a lot like Engineering in WOW(pardon equating that evil MMO to this game but its what most people have played).