Yes, a new 64-build for BB is a reality. BBLean Revived, the provisional title used by DBlake, its creator, is out since last November.
That's what DBlake says:
"The reason this build is x64 is because the older bbLean x64 was compiled with a much older GCC (4.5 IIRC) with performance regressions and issues; it would also refuse to compile under any newer GCC versions. I fixed those compilation and performance issues and here it is. SystemBarEx was the biggest pain to get compiled, but it works now. This bbLean branch is based on xZero's, just with a lot of changes in most of the makefiles (and minor changes to few source files) to help it build on x64; also with changes to the menu.rc structure (split in multiple files) to assist with adding menu entries. I decided that the original bbLean branch was far too out of date to work with x64 (or on modern systems) and most of it wouldn't even compile properly on x86 GCC.
The version of SystemBarEx included is also a combination of fixes from his source (some older source I found on his github) and the original. I tried to keep everything as vanilla as I could. There are still a few regressions I have to fix yet (menu separators disappearing on reboot, menu glyphs disappearing on reboot), but for the most part it's stable."
bblean_revived_1.18.0-x64.zip 1.08MB 413 downloads