What you may be referring to is the income tax exemption you when working overseas for a company, subject to certain criteria. The exemption appears to be $91,400 for 2008. Here are few links on the subject but the article is a little dated. It appears IRS publication 54 covers this topic. http://moneycentral.msn.com/content/Taxes/Cutyourtaxes/P119350.asp http://www.irs.gov/publications/p54/index.html
I looked into Mauritius about 15 years ago. At that time I think they would let you in if you had some reasonable amount of $$. 10% tax rate, stable govt. You would have to know or learn French to live there. http://www.state.gov/r/pa/ei/bgn/2833.htm
Singapore is a good choice. Some people lament a lack of 'personal freedom,' while others see this more as a lack of crime and violence. Jim Rogers traveled around the world twice, visiting almost every country and major city on the planet, and he decided to move to Singapore. At one point I moved to Singapore and obtained PR status - it is not terribly difficult. Esp. if you form a nominal business and make a real go at it. The gov't is quite enlightened in that they will grant you residency in order to let you have a go at it. No complaints.
one wonders why so many try to get into the US, why someone would give it up easily without understanding all the issues about why not to. For example, something unexpected happens to blot your stay in the new country. Where do you go, again?