Fresh news from XNU developers:
27 Nov '08 OK. The merge is done. All changes verified. A whole lot of bugs on the Issues page should now be fixed. No one needs to update the bootloader anymore. Should work without any options on P4, AMD whatever cpu you have. No patching needed, AMD people can update straight from apple software update. Intel and AMD both now default to 64bit mode if the CPU is capable.
The RC package will be up on the Downloads section in a couple of hours as soon as we have updated the documentation. It's been a long time since beta2c, but we hope it will be worth the wait.
>>>>> Leo4all is already in the works, as it was announced it will based on 10.5.5 retail and the new 9.5 XNU kernel.
Update:
XNU 9.5 RC is ready to download from XNU download page: XNU kernel