While LTE roaming and LTE for prepaid SIMs is still not really a reality so far I was positively surprised to see that a number of network operators are already deploying LTE on several frequency bands. This is unlike UMTS which most network operators have only deployed in one band at any one location (yes, there are a few exceptions but not many).
One multi-frequency LTE deployment I have recently observed, e.g. with my inexpensive layer 1 scanner solution (for details see here and here), is the Vodafone LTE network in Den Haag in the Netherlands where they have LTE active in the 800 MHz digital dividend band as well as in the 1800 MHz band. Add to that the capacity of their 3G network on the 2.1 GHz band and it's a fair assumption they won't run out of capacity any time soon.
And the second deployment I have observed is China Mobile Hong Kong. This one is very interesting. On the 1800 MHz band they have deployed a 3 MHz carrier (!!) while further up on the frequency dial, they are on air with a 15 MHz carrier in the 2.6 GHz band. As 3 MHz isn't really all that much I wonder if that 3 MHz carrier will still be on-air in a year or two down the road when not only most but all LTE capable phones that support the 1800 MHz band also support the 2600 MHz band. Another option would be of course to get some additional 1800 MHz spectrum and then to increase the bandwidth. But I'm not into Hong Kong spectrum assignment details so I don't know if that's an option for them down the road.