I believe a very strong case has been made (surely the coincidence is too great)
Very strong case? No, just no.
You would love numerology, or
http://www.tylervigen.com/spurious-correlationsNo coincidence is too great when your source material consists of an unlimited number of potential coincidences.
1.1 My source material is rethink-your-strategy's (RYS) post.
1.2.RYS incorrectly states there are no known entities connected to BCN. He contradicts himself by mentioning Andrey N Sabelnikov
1.3 In RYS's post a compelling connection is drawn between Sabelnikov and BCN. The Russian author of the epee lib is almost certainly a BCN dev (the coincidence is too great). This is widely accepted.
2.1 The set of people involved in BCN's creation is undoubtedly small.
2.2 The set of people involved in Cryptonote's creation is undoubtedly small.
2.3 A Russian involved with the tiny BCN set has a name which translates into the only (fake) name we have to associate with CN. The first word in his surname (sabel) translates (in Dutch) to the fake Dutch name created for CN (saber). The second part of his surname ("niko") is short for Nicolas. Additionally each surname has 4 sylabbles and the names' initials can both be re-worked to spell NSA.
2.4. The chance of such a profound name collision to occur within two tiny sets is minute. This is beyond coincidence.
2.5 Sabelnikov is Saberhagen.
3.1 The above is conjecture and cannot be proven, just like everything RYS posits. However to my mind it is even more compelling. It is elegant, witty and poetic. And quite possibly/almost certainly true.
3.2 Sabelnikov has both the motive and means to create/help create cryptonote (inc presumed botnet skills discovered in Jan 2012).