Most tax advisers I spoke with recommended against treating this as an in-kind exchange anyways.
This year, the case for 'in-kind' exchange might be best for Bitcoin and its baby Bitcoins (Bitcoin Cash and Bitcoin Gold) – the functional differences are initially miniscule, though likely to grow in time.
You could always play with fire and try this for your 2016 and 2017 transactions, but if you get audited, expect penalties.
> Investors in bitcoin and other virtual currencies would lose a lucrative tax break…"
It also reports, without caveats (or attribution to "some say") that the characterization has been used successfully, so far, in the absence of an explicit prohibition:
> Under current law, such trades have been protected under a provision that allows investors to defer capital gains taxes on so-called “like-kind exchanges”
Several of the tax attorneys quoted advance the interpretation that this treatment will only stop on January 1, 2018 under the new bill.
Of course, there's a risk given the ambiguities also mentioned in the article. But the fact that it required legislation, with a future-effective-date, to clarify may give more cover to those using the treatment before that date – and focus discretionary enforcement on clearer cases in 2018.