
Alternative recipes are [Enchant Bracer - Major Dodge] or [Enchant Cloak - Superior Intellect]. It doesn't really matter which one you make because you can combine 5 Spirit Dust into 1 Mysterious essence. These recipes also gives you 5 skill points instead of 2. The best way would be to make a few from every recipe because it will be easier to sell them.
From “The Burning Crusade” expansion, weapons like Klinge der Zauberei, Die Nachtklinge and recipes for different weapons are really valuable. The best example is Pläne: Teufelsstahlangschwert, worth 500.000+ Gold. These items are World Drops, you can find them in all raids and dungeons. I don’t know any Open World Drops, but that does not mean there are none. Another great transmog source are world bosses and rare spawns on Outland.