This doesn't quite answer the question that you're asking, but there's a semi-old research paper that seems related to what you want: http://www.cgl.uwaterloo.ca/csk/projects/escherization/ No readily-usable scripts that I'm aware of unfortunately.
That is an interesting read, thank you. You might also describe what I'm doing as trying to efficiently pack a polygon with non-overlapping images, then tessellating that polygon as a method of repetition. Easy to conceive with squares or triangles, but the pentagons in OP's link would produce more organic patterns in my opinion.
Ahh, neat! That sounds like it results in some nice patterns. In that case, this paper might be more relevant http://www.cse.cuhk.edu.hk/~ttwong/papers/pad/pad.html. Its related work section should also have some good references to other things like this. For the most part they'll likely be too complex to make them worth implementing, but it might still be interesting or give you some inspiration for new ideas.