I imagine you'd have a wider audience of people looking for just the lens, and just the body than the two bundled together. The people wanting both could still buy both, not true the other way round.
Usually the 50 isn't the first lens someone buys, so price-wise you'd probably net more separating them. Price-wise, you are looking at a value of about $1500-2k on ebay for those 2 items.