I have just read books on cloud computing without hand-on experience. Because there are too many tools available, I just want the best or good enough solution to build a cloud computing platform (SaaS) for medical purpose. For example, Linux and OpenSolaries are good candidates for OS. All will be based on open-source technologies with good security. I have read soem infrastructure design from Sun and Cisco. Because they may be biased, I want more comments and ideas from others. Any successful and good design guide for my reference? It is a good strat if the direction is correct. My last big project was the second largest Macau Casino, City of Dream.