> For that matter, they could also buy a piece of art for a million dollars, a year later get it appraised as worth $40 million, donate it, and then write off $39 million. Again, as far as I know this isn't strictly illegal, but it can be used to evade taxes.

This is so wrong it hurts my brain. The IRS requires using a qualified appraiser, and none of them will suddenly appraise an artwork for 40x its last sold value. The IRS aren't fools-- they'll quickly clamp down on such an anomaly.

Even if this amateur scheme were true, the individual wouldn't write off $39 million. They'll deduct the tax rate (%) of $39 million.