It’s something that we’ve been wanting for quite a long time, and a couple of days ago by stealth update DirSync for 64-bit was released to the Office 365 community.
You can read more about it here: http://community.office365.com/en-us/w/sso/555.aspx
We’re yet to deploy it ourselves, although we were just about to get a few customers to set up 32-bit servers in their environments so we could get DirSync going – so now we don’t need to!
Realistically there should be no difference between the 32 & 64 bit versions except for platform compatability, so if it works as expected there won’t be a need for a follow-up blog post. 🙂