Thanks!

Yeah, I'll definitely try the randomised greedy algorithm when I get time, I think it should be fairly straightforward now that I have the sprite collision primitives in there.

No problem at all if you want to reimplement in another language, the license is BSD: https://github.com/jasondavies/d3-cloud/blob/master/LICENSE

I'm guessing it will be blazingly fast using the bitwise operations in C/C++. :)