How to make a 'vector-grayscale' (shades of grey to a vector bitmap)

[paljasken]

I've been thinking about something for a while now, and tought "Maybe the friendly people of talkgraphics have a easy solution for my porblem".

I want to create graphic that can be printed on a T-shirt in one color. Because it's not digitaly printed but in the old way, I can only use one color and can't use grayscale. But... and here's the problem: I want the whole graphic to be vector artwork. So no bitmapping for me, I only want vectors.

In the example included you can see how I tried it, but unfortionatly, it's very time consuming and far from precise.

Does anyone have an idea how to do this in a acurate way?

I've also added the artwork I want to use this technique on.