Originally Posted by augustya
So a iPad user in a non U.S country should as of now count only on his luck hoping that the LTE Network in his country by only sheer virtue of luck uses the same frequency that the iPad-3 uses and that is how he gets to use the 4G on iPad-3 (which looks very unlikely)
No luck needed. You can just count on the LTE networks not being compatible, and therefore the 2012 iPad won't support LTE in your country, if it has an LTE network. Your government should have a commission or entity that determines how radio frequencies are used.
For instance, in the UK, their telecommunications entity has allocated 800 MHz, 1800 MHz, and maybe 2600 MHz spectrum for use with LTE networks. They just did this recently, and currently do not have a LTE network. I believe one of the local, smaller operators will start an LTE network late this year or next. And a build out with multiple networks likely won't happen until 2014 in the UK. Each country will similarly allocate a set of spectrum for LTE. All you need to do is ask.
Currently, LTE chipset are designed to support frequencies of existing networks. The USA, long considered some strange telecommunications backwater, is considered to be largest LTE market with the biggest LTE networks. So, it's basically Apple's only path right now. It wouldn't be a smart thing for Apple, more importantly, the radio chipset manufacturer to support a theoretical network that's not being built yet.
Like I said earlier, it's not a big loss if you are not in the USA or Canada. Many other countries support 21 Mbit/s HSPA+ and 42 Mbit/s DC-HSPA. The data rates from these networks are close enough to LTE in the USA that it really won't be that different for most users. Both LTE iPads (Verizon and ATT) are unlocked 3G (HSPA) devices and will support this higher performance HSPA networks.
If you are in a country that doesn't have a supported HSPA+ network nor an LTE network, not sure what I can tell you. The iPad WiFi+4G supports UMTS (good old "3G"), so you can still use it on the go. So, it's still a win, unless this UMTS network isn't on a supported frequency. If the network is not an iPad supported network, I suggest buying the WiFi version or some other tablet with the supported cellular wireless technology.