A very important and good question : “For one customer we have about a dozen individual websites for different countries and languages, with different TLDs under one IP number. Is this okay for Google or do you prefer one IP number per country TLD”?
In his latest video, Google’s head of web spam Team, Matt Cutts said that in an ideal world, it will be great if you can have separate IP addresses for.com,. co. uk,. fr and have them placed in UK, France or Germany. But in general, as long as you have different top level country code domains, Google is able to distinguish between them. So, you don’t have to put them all on one IP address. Google does take the TLD as a very strong indicator.