Reminiscent of this now laughable vaporware "story" from June 2015:
http://www.fonearena.com/blog/14372...orlds-highest-capacity-sd-card-announced.html
There is just about no chance that the first 512GB microSDXC card won't come from one of two major dominant players, either Samsung, or SanDisk (Western Digital), with a small outside chance they could be miraculously beaten to market by either Crucial (Micron), or Toshiba.
Only those 4 dominant major players have the ability to develop the next generation of storage capacity in a microSDXC, the resources involved for this are not trivial.
About the only way a company like Integral could be first to market with such a card is by buying an exclusive on it from Samsung or SanDisk, assuming either of those majors wanted to accept money in exchange for an early 1-2 month exclusive branding by someone like Integral.