The lag on iPad launch here has nothing to do with import taxes. Actually, brazilian-made iPads will cost nearly the same as the imported ones. This is explained partially by the higher labour costs, but it doesn't explain almost imperceptible price cuts. Besides zero import taxes, there are other local subsides.
So, in truth, Apple will increase its profits when produce in Brazil. That is, Apple helps local people bringing more jobs, and government helps Apple with tax cuts while allowing them to sell iStuff for nearly the same price of the imported ones. It's a win-win.
Well it's fair to say that until they get the infrastructure to produce in Brazil (which they are working on), Brazilians aren't going to see any early releases for the sake that the higher costs hurt sale numbers. It's interesting to argue that they will actually be the same price regardless, but I don't buy that argument. Why? Because if that was the case Apple wouldn't bother working on production in Brazil. They are going to be saving money by doing so. Apple will profit from being in Brazil and push more units (thanks to government and local subsidies as you have pointed out). The whole purpose of producing the iPhone 4S in Brazil was to lower the retail cost, while retaining profit, so that they could push better numbers in the region.
If there isn't an import tax driving up the cost of the iPad in Brazil, then what is? Because the MacRumors article I read detailing the iPhone 4S production explicitly mentioned this tax.