Earlier today, with some help from the R3 research team (thanks for the grammar fixes!), I shipped a new paper to the consortium members. This paper discusses several issues and challenges facing a Bitcoin-based ETF that was originally proposed a couple years ago by the Winklevoss twins (commonly called the COIN ETF). It specifically looks at questions publicly raised by the SEC.
It bears mentioning that R3 itself is not in any shape or fashion involved with this ETF or in using the Bitcoin network. This (tangential) paper solely represents my views and not those of my employer or companies I advise. I worked on it in my spare time.
R3 typically makes research papers available 3-6 months after sending it to members, so check back here later next spring or summer to see if it has been posted.