Knife Training

Does anyone have a source for training knives that leave a visible mark on the training partner. Many of us have tried chalk, markers, pens, etc in the past but I am looking for something more sophisticated that will actually have the feel / handling of a real knife.

Use some of the common real feel training knives that are black. You can put chalk on them. Wear black clothes while training. The white chalk will show on the clothes of where the knife strikes.

Humbly,

If you use a standard rubber tanto available in most martial arts shops along with a white t-shirt.
The silver finish on the blade wears off quick and the black rubber underneath marks a white t-shirt lovely.

This is an excellent tool for knife training. You just have to be careful about going too hard because it is made of metal and can still hurt:
http://www.nolieblades.com/

Thanks to all!