We had one in about a year ago. It had about 100K miles on it, with a blown turbo. We sold it for $9K WITH the blown turbo. The buyer didn't care - he was going to put a new turbo on it, do all the maintenance, and would STILL be in a positive equity position.
Do they show that value on NADA? Not really - but it's a case of the car itself holds that value. It's like leasing a WRX. You lease a $30K car with $420 per month payments for 3 years, the residual value (which is set at the start of the lease) is about $18K - but the actual VALUE is $5 - 6K ABOVE that. (Go look at clean retail on a 2011 WRX with 36K miles on it - clean retail is $24K. On a car that cost $30K brand new.)