For lqt, for example, most of the code is probably automatically generated: as long as you are able to run the generator, the maintenance burden might be light.
Yes, the binding is completely generated by parsing the headers directly. So everything that can be bound to Lua will be bound (there are some esoteric things in the blacklist).
I see lqt just reached the 0.9 stage, it should be quite stable now.
Correction, will be 1.0 soon - the API of the binding is relatively stable for a long time already. The library stable as long as you refrain from using multithreading (you also suffer from multithreading forced onto you by Qt, but I did some changes which minimize the exposure).
Since this is a generator, it will generate bindings for whatever version of Qt you run it against (although I didn't test it on Qt 5.0 yet). An API upgrade for a new version of Qt is just a single "make" away :)
