{as of May 10, 2019 10:00am CST US}
For anyone who's been waiting for an OP Expansion Kit and wants to avoid shipping charges, I just got an email from B&H Photo/Video that the 'kits' are finally available from them.  FWIW, I was on a waitlist there since the first release!  Don't ask me for a link to B&H... do your own link search on Google, Bing, DuckDuckGo, etc.  ;-)

Hello and good day WebParrot. Thank you for reaching out and for the information you have shared with us today. Great find and thank you for your support.