Mobile Network aggregator in Brasil

I read (with mild interest) this Economist article on the woes of Brazilian mobile operators: Telecommunications in Brazil - The next big blackout?

I picked up this statistic:  A 2009 World Bank study found that raising mobile-phone penetration in a developing country by ten percentage points increased GDP growth by 0.8% a year.

But what really got my attention was this statement:

Venko, a local phone maker, now offers a handset that holds four SIM cards, automatically choosing the cheapest for each call.

That's arbitrage!