Well as I said, something is currently being worked on, to replace the current dye system with a dying dummy system that takes money. I have no idea when this will be ready or what is the current status with it. Certain aspect of this new system are still being thought and worked on, so it could be there with the next update as well as it could be there only in a month or even more.
You should try asking EO or Arawn, I'm not 100% sure, but I believe one of them have been working on this lately, perhaps they could give you more detail than me if you ask them.
As for having preview of color and testing it on your outfit, I have two solution that I can suggest you.
First one is the toolset. Recreate your outfit there and you can play with the colors as much as you want, it's easy and quick once you get used to it. Use this to find out what number represent each color in the toolset color grid.
http://www.amethyst-dragon.com/nwn/Images/colors_leather.htmThis first solution is the fastest for trying multiple different color, but also more complicated than the second one.
My second solution, which I've been using just as much as the first one is making a dummy character and leaving it in the starting area. There you can recreate your clothe quite easily by noting the number of the different part of your outfit and quickly recreate it on the char in the starting area. From there you can play with color as much as you want using the dying dummy.
This second solution takes more time, but it's much more easier if you don't want to deal with the toolset.
Hope this will be of help.
