Surprised to see this thresd resurface. Basically, I did as I planned, flogged the skinning and mining until I had over 20K gold in the till. Then I dropped skinning and took up jewel crafting. By prospecting most of my own mats, i managed to actually increase my till somewhat while leveling my J C through 525 - only to learn that the best gems I can craft are soulbound and cannot be sold or even given away and there's no demand for 99% of the gems you CAN sell . So, while it looks like I could continue to incrementally increase my wealth with the JC, it'd be like trying to put out a forest fire with an eye-dropper and a thimble.
Ergo, I'm now thinking of another career change to either blacksmithing or engineering, both of which would dovetail with my mining.
I have no quibble with the two-profession active limit, but itd be nice if the'd give you an achievement based on the total number of professions your alt has mastered, even when now inactive.
A shot in the back saves nine.