I doubt this will happen any time soon. It's very much to SE's advantage to give the impression that promotional items are ones where, if you don't buy them when you have the chance, you'll never have the chance again (or, at least, not for many years). This encourages players interested in obtaining the promo items to BUY NOW, rather than sit back and wait, confident that it will be available at a reduced price (minus the physical merchandice they may or may not want) in the cash shop eventually.

Even if SE eventually gives in and makes these items available, with the game as young as it is they very much want to make you believe that if you wait to buy, you may never get it at all. Putting them in the cash shop now would undermine that illusion.