When you show the sale, be sure to apply an appropriate percentage of business use for ALL YEARS. e.g. 60,000 miles and 15,000 business miles over 4 years gives a 25%business use. Sale price = 25% of total, Basis = 25% of original cost less the depreciation portion of standard mileage rate. 

Personally, I don't think I would go there, but if you do make sure you charge appropriately for the time involved to get it right.