If approved, new citizens will enjoy visa-free access to nearly 120 countries, which include the United Kingdom, France and Canada.
In Europe, Austria stands as the lone country where citizenship by investment is possible, according to Henley and Partners.
The route, taken by few and accomplished by even fewer, can happen for "rendering exceptional services in the interest of the Republic," according to an Austrian government website. One such service that has cleared prior clients, added Henley & Partners, is a direct investment of $10 million -- a claim reportedly refuted by an Austrian government spokeswoman based in Washington, D.C.
Still, successful applicants for Austrian citizenship can live in a country whose capital, Vienna, ranked as the world's best city for quality of life in a 2012 Mercer survey.
But you get what you pay for: Austria, with its 50% personal income tax rate, ranks among one of the highest in the world. A workaround, according to Henley & Partners, is simply to live elsewhere in Europe. Only Austrian citizens who actually reside in the country are subject to taxes.
An Austrian passport easily gives that option by opening many borders. The country is a member of the Schengen Area with its 26 countries spanning most of western Europe sharing common borders without immigration control -- not to mention more than 160 countries in total around the world -- on par with Australia and Canada.
5. Hong Kong
While citizenship-by-investment in Hong Kong is not a possibility, residency-by-investment is. And this Chinese territory's tax rate of just 15% stands as one of this city's biggest draws.
"In all of Asia, in terms of freedom to move capital, taxation and residency requirements, Hong Kong would be the best choice," said Denny Ko, Managing Partner at Henley and Partners in Hong Kong.
Under Hong Kong's Capital Investment Entrant Scheme, or CIES, an investment of about $1.3 million gives applicants residency rights. You can buy stocks in companies listed on the Hong Kong Stock Exchange, debt securities in airport or railway companies or certificates of deposits that mature after just one year.
In addition to enjoying one of the lowest tax rates in the world, residents can use the city's well-regarded public health care system -- just $13 to see an outpatient specialist versus about $150 for non-residents.
Permanent residents have also gotten money back from the government. Under Hong Kong's "Scheme $6,000" whose aim is "to leave wealth with the people," more than 6 million people successfully registered to receive roughly US$770 each. Doing the math, that's potentially $4.6 billion back to the people since the program began in the summer of 2011. Hong Kong is waiting on word of the program's continuance.
Hong Kong also tempts with a rare nexus of natural and man-made architecture. Lush mountains with 300 kilometers of hiking trails crisscross the Chinese Special Administrative Region (SAR); a Star Ferry ride traversing Asia's largest harbor, Victoria Harbor, presents passengers with one of the world's most iconic skylines. In fact, Hong Kong boasts the most skyscrapers in the world -- more than 1,300 at current count -- besting New York's 700 and Tokyo's nearly 400, according to global building data provider Emporis.
Nearly 18,000 people have gained residency by investment in Hong Kong. To maintain permanent residency status, just one visit every three years is required.
In 2012, human resources consultancy ECA International ranked Hong Kong as Asia's third most livable city, with Sydney coming in second.
However Singapore ranked as Asia's number one livable city in 2012, according to ECA International.
Similar to Hong Kong, the Lion City's personal income tax rates are among the lowest in Asia -- ranging from 15% to 20% depending on income bracket, according to auditing firm KPMG.
But "for Singapore, it would not be so easy" to become a permanent resident, said Jacqueline Low, COO at immigration services firm Janus. "The criteria are quite high."
Potential applicants must have a three-year track record of business and entrepreneurial experience, Low adds. They must also prove past profitability -- annual revenues of some $160 million in real estate and construction-related industries or revenues of about $40 million for all other industries, including pharmaceuticals and manufacturing.
With such foundations, candidates can then apply to Singapore's sole track to permanent residency, the Global Investor Program. This scheme requires an investment of nearly $2 million. The funds can go towards starting a new business or expand one already in operation. Money can also be routed to an approved list of funds that help grow targeted industries ranging from nanotechnology, healthcare and clean energy.
Coupled with low tax rates, applicants who successfully gain permanent resident status can then access healthcare subsidies ranging from 15% to 75%, education subsidies for their children, child-care subsidies and tax deferrals.
Cons for permanent residency include mandatory military service for second-generation males who are also permanent residents, well-known censorship of press freedoms and seasonal smog blankets from Indonesian forest fires.
The Singaporean government does not release information on the numbers of candidates or successful GIP applicants, says Janus' Low. However, since the middle of 2012 she notes "Singapore's immigration policies have been tightened across the board because of the sentiments on the ground" -- a reference to growing public unease over the number of migrants to the city.