Didn't mean for this to be a "what type of skill should I choose" type of thread but what about slicing with synthweaving and archaeology? I can use slicing at 50 for augments and just use it for extra money while leveling, and with archaeology I don't think synthweaving uses color crystals at all so I can sell those for credits too. I'm liking the sound of that.
Colour crystals don't sell very well, I'm afraid. It's the gemstones that are sought-after, and they're acquired through Treasure Hunting.
But synthweaving can work, too. Some of the nicer-looking orange gear is Lower-level, and is very cheap to make. You can easily sell them 9-19k apiece, depending on demand\supply ratio. Just make sure you find the schematics.