The newest Japanese release of the manga is already slated to come out at the end of this month! Also called "bunko collection" on the front covers, these "bunkobon" (文庫) are a commonly released format in Japan. They are smaller (usually A6 size paper or 105×148mm or 4.1"×5.8") and are designed to be more portable and affordable. It hasn't been revealed exactly what the dimensions of this particular release are but it will be significantly smaller than the Complete Edition. The pre-order price through Amazon.jp is 842 JPY (about $7.50 USD) which is about half of what fans paid for the Complete Edition.

Pre-order Vol. 1 here
Pre-order Vol. 2 here

Also, don't let the "affordable" idea fool you - apparently bunkobon generally are printed and bound so that they are durable as well. I guess they don't want the books to fall apart after being shoved in and out of your purse a few times a day XD.

As you can see under the spoiler, the cover images have been recycled from the Complete Edition. The whole point of these releases is so that they are cheaper so this is not surprising.

Cover Images of Vol 1 & 2:

This new version was actually announced back in June. The plan is to release two per month starting this September 28. The official website seems to say that there will be color prints included though it doesn't specify how many.

In addition, it seems that there will be a limited bookmark included for people who purchase through the fanclub website. It will be one of five prints at random shown under the spoiler here:

bookmark pics:

Again, this is a Japanese language release only. Given the decision to supersize the North American release, I sort of have my doubts that this version will end up launching at all over here, but that's my speculation talking now.

How many versions will we have by the time 30th anniversary rolls around I wonder?


Sources:
http://sailormoon-official.com/comics/news/bunko_collection.php
http://sailormoon-official.com/comics/news/0913_NaokoTakeuchi_collection.php
http://sailormoon-official.com/comics/news/0903_NaokoTakeuchi_collection.php
http://sailormoonnews.com/2018/09/10/as-the-new-eternal-editions-of-the-sailor-moon-manga-are-released-in-english-a-smaller-bunkobon-version-is-coming-to-japan-september-28th/

++++

Meanwhile, it looks like there's been no further news about the next volume of the novelized series that began its release earlier this summer. We really are awash in Sailor Moon print media, though!!