Best cash farming class with limited play time?

[M.J.]

If you want to maximize your time I'd say enchanter.

Reliable single pulls and CC indoors and outdoors, faction adjusting spells and illusions to make repairing factions you've wrecked repairable, in demand as both DPS and CC for most high level groups that aren't limited on mobs, best charisma for maximizing vendoring items for plat, access to undercon mobs in many zones that make duoing with a priest very easy or that can be memblurred and allowed to heal up before a recharm.

If you don't like the risk of charm, necro is your best bet, but they're weak at root rotting at present so they don't fair so well in tight spaces or in areas with pathing issues - which is pretty much every dungeon and any zone that isn't as flat as the Karanas.