I buy and sell faction/deadspace/officer mods, ships, skill-books and implants with traders covering all 5 main trade hubs (Jita, Amarr, Dodixie, Hek and Rens) plus secondary hubs in most other empire regions. I have 24 active traders, 3 on Jita (one each for mods, implants and skillbooks), 2 in another region, another 19 each covering a different region and a couple spare traders that are not actively trading.
In April, I made a profit of 38 billion after expenses.
Current net worth is 544 billion with roughly half in cash and market escrow. Most of the rest is in sell orders and recently acquired assets I haven't gotten around to posting for sale yet. Very little is in assets I don't intend to sell soon, with maybe 4 billion worth of ships and fittings I keep for my own use.