Seems highly unlikely that we'll get anything from this.
Bill P and Joe T are understandably on bad terms with AntiGravity from what I read here, and AG is the last ones who claimed to be owners of it.
Mick T was the original owner, but he doesn't have a webpage anymore - only I can find on him is a Linked-In page, and berfore one knows for sure who owns the designs, I don't see that it would be smart to nag on Mick about the BoXeR.
Dream situation would be that the owners was someone who was still sympathetic to the Amiga Community and would put all the source, designs and documents still available on a googe.code project page and open it up for people.
Also, the dream situation would be that they either followed amiga.org and did so now on their own initiative or that Bill P or Joe T knew it was Mick and asked him to do it.
If it's AntiGravity, it would seem that the Illuminati has had them burn all the documents... :-/