Regarding that... do you by any chance have a contact who knows about 8-bit BBC BASIC licensing? I know the 32bit ARM variant is open sourced, but so far I didn't manage to find out if that license applies to 8 bit BBC BASIC as well.
Anyway, to answer your question… to the best of my knowledge, the rights are owned by Richard Russell, who wrote the Windows, MS-DOS, Z80 and SDL versions of BBC BASIC. He also, I believe, now has some sort of Android app-maker based on BBC BASIC. And he also ran a BBC BASIC support group at one time (I don't know whether it's still on the go). I've never had personal contact with him, but his name has come up many a time and if anyone can help you in this excellent venture, it'll surely be him. I'd hope he'll prove approachable and helpful.
His website is here:
He's still selling BBC BASIC for Windows as a commercial product (£30), but he provides many other versions on his site for free, and there are still some obscure versions you can download from there (such as one for Tatung Einstein). You can get a version for CP/M for free, too.
I didn't want to answer in the ZX-Uno thread, because I think this fits better here.
Anyway, Richard Russel's zx80 BBC basic source code is available under the zlib license:
Unfortunately, this is completely independent of the 6502 BBC basic at http://mdfs.net/Software/BBCBasic/6502/. Even though the source is available and a C64 port already exists, this is based on the original BBC Basic from Acorn, and the rights presumably belong to whichever entity now owns the right to the Acorn home computer division...