Ehh.... that's a tough one alright.

I'd start with what Mr Tax Man thinks Steem is. Maybe it doesn't even know Steem exists and only cares about what comes out of an exchange as EUR. Tax Man acknowledges the existence of EUR, it is very happy do tax those!

The thing is, in my opinion, that for all intents and purposes Steem is only a system of points. Some people think those points have value but the state and by extension the EU don't attribute value to that point system and as a consequence, no legal protection, no bail-outs, no safety net.

If the state does not recognize the value of a currency-like point system, then said state does not provide the facilities and services citizens need to incorporate it in the state's recognized economic system.

Meaning, no services provided by the state, no taxes. We pay taxes so the state provides us, the society, with services we need, like health care, a legal system, police services and the tax system itself.

Conclusion, until there's no recognition of Steem as a currency, the only thing that can be taxed is the EUR that comes out of an exchange. Because that EUR is backed by services and regulations provided by the state. The state spends money and a lot of it to maintain that service package. It does not spend a cent with Steem at all. So no taxes at Steem's internal economic mechanisms.

I'm sorry i didn't dive into what you were trying to go for. You took a lot of effort in writing this and I read it all, but I think you're overthinking this, probably because, as an accountant, this is like candy for the mind. :P

In any case, I found the SP part quite interesting. I understand the need to discuss this issue for prosperity, maybe some legislator will read this, so I'll indulge you:

SP is no more that access to the reward pool. So...you're given the right to access some sort of fund...or maybe, to reap daily dividends of some asset, in this case the Steem Blockchain itself, as curation/author rewards.

I really like the dividend comparison to rewards, taxation-wise it might not be the best for us earners...but it does fit nicely as a concept. The odd thing is that we, as stakeholders (SP is like putting steem at stake as well) have to participate in this convoluted meritocratic system to earn rights to those dividends, but that's an internal matter that should not concern TaxMan...maybe LegalMan though...I'm thinking about human rights n' stuff...

Anyway, point is, as dividends there's a taxation case-scenario already predicted and supported by the State, so maybe it's not so complicated after all, I guess?

Btw, I joined Steem this year so I can't say how I do my taxes and I never earned money from any other crypto so...sorry, 'cause I really like where this is going. Actually I can't wait for the second part! :)

Cheers