Where in the USA can be bought the iPhone 5 Modell A1429 GSM?

Get the Verizon iPhone, which is model A1429, it's comes GSM carrier unlocked out of the box. Do not get the Sprint or AT&T version.

I strongly recommend that you do NOT buy a Verizon-model iPhone. You would get no service nor support for using that iPhone anywhere but in the US (the same would be true of any US-sold iPhone). I strongly suggest you wait and purchase an iPhone in the country in which you live.

As to LTE compatibility of any iPhone 5, see:

http://www.apple.com/iphone/LTE/

Regards.

It works: https://discussions.apple.com/thread/4761497

Sure it works. But you cannot get warranty service nor support from Apple for a Verizon iPhone anywhere but in the US.

Wrong.

This is an Apple product, purchased from an Apple Store. I am covered world-wide.

Wrong. The iPhone warranty is valid in the country where it is purchased. The exception being the European Union.

Ditto wrong. The warranty on the iPhone is not international. A US iPhone's warranty is valid only in the US. This is particularly true with a US-only model such as the Verizon iPhones. This has been verified countless times in these forums by users who believed as you do and found out the truth to their sorrow, as you also will should your Verizon-model iPhone ever need service when you're not in the US.

That is not completely correct. From the US warranty:

IMPORTANT RESTRICTION FOR iPHONE AND iPAD SERVICE.

Apple may restrict warranty service for iPhone and iPad to the country where Apple or its Authorized Distributors originally sold the device.

Fact, I replaced my Ipad2 in a out-of-warranty service in the US while it was bought in Europe.

Our statements are completely correct. An iPad is a different matter. Apple generally does not restrict warranty on iPads (though if you'd have purchased a Verizon-model iPad 2 and tried to get it serviced in Europe, you'd have found out that the iPad would haven't been covered there either), but they absolutely do for iPhones. Again, this has been confirmed over and over by users who, like you, didn't believe what they were told but found out later the hard way.

Once again, a US-sold iPhone will be supported by Apple only in the US. You may not believe us now, but you'll find out should you ever need service and try to get it in Europe.

You stated it was an OUT-OF-WARRANTY service, therefore it was probably irrelevant where you bought the iPad vis-a-vis where it was service. The story would have been different if you tried to get WARRANTY service for your iPad.

In any case, the iPhone warranty is NOT international.

The text of the warranty is crystal clear:

Apple may restrict warranty service for iPhone [...] to the country where [...] originally sold [...].

So, it may happen. It likely happens, but the warranty does not mandate that it will happen.

Trust us, in the case of the iPhone, it WILL happen.

PS I suggest you do a search of this forum before you continue to affirm something which is incorrect.

That is a good point. It may very well be that OOW service is done regardless of country of purchase.

Anyone has a good idea of how to test the Warranty service outside the country of purchase?