You can pretty much already do this actually.
You can sell cartel packs / costumes, and if you ask around in chat you'll likely find someone rich enough to constantly buy off you if you want.
60$ for 500k would actually be a terrible rate on my server for example, since selling cartel packs would get you way way way more than that.
Items you buy off the cartel market are bound to you for 36 hours, after which if you havent bound them to you by using them you can put them up on the gtn.
Also sending your crew out on gathering missions can be a very safe source of materials.
The easiest I can think of would be to take slicing for the Purple Tech parts which sell well, and Possibly Underworld trading/Diplomacy for your mission skill, and fill in with whatever gathering skill you wish for your third slot.(This is assuming you don't want to craft, of course).