Fishface:
As far as the unlimited transfers goes, the amount is, unfortunately a central bank limitation. There are others as well that are unique to Argentina. For example, it is illegal for a person to transfer money directly from Argentina to Jersey and a few other offshore places. Hence, there's nothing that HSBC can do as the limits are imposed by the government. This is the big issue that HSBC runs into with a lot of the variations in the service.
Once again, yes, you get free transfers between same-name accounts with HSBC Premier, but if you don't have the DNI, then you will be subject to Central Bank rules. i. e. a max of USD 3000 per month.
On the matter of the DNI, you can open a savings account (which are more useful here in Argentina than in the USA) and get a banelco/Visa debit card for both Peso AND Dollar accounts without holding the DNI. You have to provide papers like a utility bill, etc., but the CUIL works. The RMs who handle the accounts can give you the full list of what's needed.
As far as the amount to qualify, it depends on the method used. For example, the amount is lower is a company uses payroll, etc. It's not my area of expertise with the bank, so I can't say off hand. But yes, the amount needed to qualify varies from country to country. It's significantly higher in the USA, UK, and Hong Kong than it is here And yes, it's a loophole that means that you could qualify here and then go back and be a Premier customer automatically in whatever your home country is without being subject to their regulations for qualifications.