Should this be regarded as capital gains from currency speculation, when it comes to taxation, or how does something like this look to a tax attorney or accountant?
The government would have to consider Bitcoins as a currency for it to be taxed like a currency. Right now it has no status identified for legal purposes so no way to tax it. I am sure that several governments are looking in to it as we speak. Death and taxes
It doesn't matter if the stuff is tangible or imaginary. You would owe taxes for mining World Of Warcraft coins if you sell them. You would owe taxes for picking up cans off of the street and recycling.
How much you owe can change with how you earned the money, but if you earned money you owe taxes. Only two things in life are certain. Taxes is one of them.