On the BBC-Micro mailing list, Anders Carlsson recently posted a pointer to an interesting thread from Feb 2008 about Mark McDougall's project to implement a BBC Micro on FPGA.

This is, I think, the PACE project, which uses the T65 core - and Mark's adventure helped to improve that core: as is often the case, the B bit of the status register wasn't quite right. See here

The bad news is, I can't find any revision of the T65 core later than v302, which is from Jan 2008, and pre-dates this bug fix. (*)

(*) Edit: in fact, Mark McDougall has confirmed that the version in the pacedev repository has the fix.
(I was looking at the wrong file and couldn't see it.)

Much later edit: Mike Stirling made a BBC Micro on a dev board using this core..