If you are prepared to keep one in excellent condition for years and years, yeah you might double you money. Original iPod, or iPhone in pristine condition can make you some money, but that is years..... down the line.\
My guess the Space Black SS might be the most rare, due to price, but given it can scratch, you are going to have keep it locked up.
The edition, price is too high for it to ever become a collectable in my opinion. Not even collectors will pay RRP for those.