Unless I'm mistaken, the only actual rule change from last year is the new nose rules. So technically they could just stick a 2015 nose on the 2014 car. There will be some packaging issues for the revised 2015 engines which involve hacking at the carbon fibre here and there as well.
Of course the car would be dog slow as a result but they'd get something to the grid. You have to admire their determination but I can't understand why?