Changing Armor on Character Images

There are a number of RPGs (e.g. Diablo, Fallout, Neverwinter Nights) where characters with different armor/clothes have different images.

Presumably, they're reusing some of the same art and just adding on the different kinds of armor.

For 3d models, I've been told that people can change textures and add weapons and such by just attaching them to a point on the model. I've also seen a website about "2d models", but that seems rather excessive.

I want to work with solely with 2d art, and I don't want to make alot of work for the artists.

The way I have my RPG set up now, character images contain 3 "special" colors (for clothes 1, clothes 2, and skin, respectively) that are replaced by other colors when the character is loaded into the game. This makes it easy to get lots of character images, but the quality is rather low.

An artist suggested having a gradient of color in the image and then replacing the gradient but leaving the change in the color the same. If red were the color that were being replaced, this would effectively make it impossible to use any shade of red as a regular color in the image. Obviously, that's unacceptable.

I thought about replacing the color with a texture using TexturePaint, and that is one option.

Another option would be to have some sort of text-based drawing mini-language that would make it easy to change the colors, but that would never appeal to any artist.

The "2d models" are also an option. Essentially, the body parts would be drawn seperately and could be substituted in. The big issue for that is that it would be alot of work (mostly for the artist, but also for the programmer) for a freeware game.

Has anyone else done something like this? I'm interested in finding a better solution.