I've been doing this for a long time, and I hate to be the bearer of bad news, but you usually get killed trying to resell high end models.
Keep in mind that in doing so, all the demographics and trends are working against you. You may be advertising your big disk, but that only matters to a fraction of buyers. Furthermore, "power" users will often be lured in by the shiny features offered by the then-"new" models, which further make your used model less attractive by comparison.
I think that, after the next revision is released, you'll find getting $2000 for a 512GB model to be extremely unlikely (unless you meant the 2.3/16/512 one, in which case $2000 might be about right, but with a more narrow market of potential buyers). I wouldn't value the 1TB drive any more than about $150 more, personally. Yes, you might be able to be patient enough to find the needle-in-the-haystack buyer who cares about only disk space and is willing to pay you a premium. But it won't be easy unless you go to eBay, where resale values already get killed—and that's before eBay and PayPal take their cut.
I'm sure someone will chime in this thread with their anecdotal story of how they managed to do it, but that would miss the point. Those stories are the exception, not the rule. I've actually made money selling an old MacBook Pro and buying a new, more capable revision. Is that the norm, and should that be the expectation? Of course not. Same principle applies.