Great post, thanks for sharing your thoughts. If one buyer does have over 5% of the OS then we should have more information soon. It's not clear that all of the 25M in buys yesterday went to the same buyer, so unless that is the case we may not get that further information. In other words, we don't know for sure there is a 5% owner.
You also bring up a couple of points I hadn't considered. First, I will say I think the bitcoin connection is unfounded - the twitterverse created a rumor based on someone with the name "Dave Walker" joining some bitcoin related operation, but it isn't the same guy as EIPC CEO Dave Walker.
However, just because the bitcoin story isn't the story doesn't mean there is not a story. Plenty of other options that you note could be cause for the significant volume. As you note, it could be anything from a reverse merger to a patent acquisition, to some underlying developments with the company.
Hopefully we'll have more information soon.
