I mentioned it would be possible
but sorry to get your hopes up
I looked further into it and qt5 is quite different from qt4
So it would take rewriting parts of the code
which nobody is doing :p
on the plus side there will be a new webkit for qt4.8 named qtwebkit 2.3
which will work very easy with the current code :)
but its still months away from being released (I think)
the program will still be 32-bit because 64-bit is introduced in QT5