The wikibooks and Wikijunior logo discussions were supposed to start with an advertising blitz. The last discussion, which ended abruptly with no final result failed, in part, because not enough Wikibookians participated in the discussion. Many people felt that the decision wouldn't be meaningful unless it was decided by wikibookians (or, unless wikibookians were well-represented). Because of this, before starting the new logo discussion, we made it clear that we were going to spend time advertising the discussion, and getting wikibookians involved. That effort appears to be bearing fruit, as we've been able to successfully post advertisments to en.wb, de.wb, fr.wb, pt.wb, ru.wb, simple.wb, pl.wb, and es.wb (not listed in any particular order). According to Alexa, this should make up about 82% of the total wikibooks population, which is a good starting point.
I can't really think of an instance where we needed to contact and communicate with the other language wikibooks projects. It's an issue that doesnt come up much. The effort that it has taken to find translators for all these projects has not been negligible, and the #wikibooks chatroom has never had so many people in it as it has while we were trying to get these messages sent. Wikibooks of all languages is lucky to have so many members that are willing to help each other.
I'm starting to get excited about this, personally. Wikibooks and Wikijunior could end up with some awesome logos when this is all said and done.