Regarding sandbox I would tell that ... I dont know, actually... The client I have already downloaded. I am sure at 80% that it will be failed to enter the world without sniffs. Moreover, the cataclism experience make me ensured in necessity implementation the second connection to the server. But as you may be know it is impossible to do... So... I can build the sandbox I think, but it will be the same point as at the last cataclysm versions - most features does not work. Do you really need don't working sandbox?
Also I didnt investigated the pandarian close yet... I suppose 5.x addon will give us more surprices. Like no more update fields in the exe file (yes, I have looked through a little bit an exe)... But actually I found some data structures which are might be used to recover the update fields of objects.
Finally I just to remind you - each of builds of exe file contains the new random opcodes. I guess during the beta period it will be much more builds and versions. To complicated to finding out them every time.
At the other side I can open the sources of my sandbox... yes, I think I can... but it is written in Delphi

I also suppose that people who can really do something with it - have badly Dellphi experience than C++

For who I can give the sources I have no decision...