is there a 64-bit preview compiler available, as announced a long time ago? I wasn't able to find anything.
I really need a 64-bit compiler to target the 64-bit versions of Microsoft Office.
Not yet.
According to the latest roadmap Delphi X and Chromium seem to be the current priorities, followed by Commodore, so I'm not sure when a 64 bit preview compiler will be available.
If you want an early peek at these things, it might be worth signing up for the betas.