I don't see why Its non-standard, if you can create a new kind and make it a standard, especially if it's in the minority case. 

Only edge case I've been able to think about is what happens if there are two subsequent events claiming to be the successor of the first one, which is not going to happen in the usual case.  

 Each could contain a hash of the successor. 

 Yup, that's what I was planning too.  

 Then you just need a `head` tag, maybe, so that it builds faster. 

 💯 and a tag with the total number of events there are.