No. Amazon only has Nvidia hardware in their EC2 GPU clusters. Nvidia is not equivalent as it is significantly slower than AMD/ATI hardware for password cracking. Eg. a top-of-the line AMD GPU brute-forces MD5 hashes about 5x faster than a top-of-the-line Nvidia GPU, see: http://golubev.com/gpuest.htm

I don't know any computing provider who rent out AMD GPUs... (This would be a startup opportunity.)