Yes, I know that Cubase 6 have that option.
The question is: if upgrading to Cubase 6, with an earlier 32-bit mode (I suppose I have to install LE4 first), is it then possible to choose between 32-bit or, as I want, 64-bit? If it is so, then the case is closed and I´m happy.
(A thinkable scenario is to sit with a Cubase 6 in 32-bit mode, if LM4 force it to be 32-bit. And maybe Steinberg indicates that since “thanks to VST Bridge technology from Steinberg, which allows 32-bit VST plug-ins to run in a 64-bit host environment”. In theory, it seems possible to run Cubase 6 in 32-bit mode while having a 64-bit OS, and a “hey, it still works dude” will not make me happy …)