This is pretty neat, watch the video. It would be great for an accessory for your truck but everyone would be calling you when your car is dead.
$4-7k? buy a trailer & small winch for $2k, or a dolly for $800
But think of all the cars you could steal 
I know the price is crazy but if you have the money its pretty sweet.
Saw one of these on one of those Repo shows a while ago. Would be good for that, or if you had a parking lot where you might need to move vehicles around a lot (thinking like college campus/mall) and you want a vehicle that does double duty. but for a normal person, just get a trailer and winch like stated.
That has repo and high end car thief written all over it.
Probably be really good for highway towing duty too where taking the time to do a traditional hookup is dangerous to the tow truck driver.