I don't see why it couldn't be done but be very careful when making the black malt: It's roasted to just shy of its ignition temperature. A bit of miscalculation and you could have a grain fire to deal with.
Was thinking about the coffee and chocolate malts more than the black malt. But I suspect that you are correct Nosybear, I may end up causing the smoke alarms to go off!
I'll be sure to cross my fingers and my eyes when I do it.