Update (01/05/16): @PointBlankSpain tweeted out today: "From 3 diff. sources: Eurotour for River 2016 in the works. Pending confirmation." Sounds like the rumblings are getting louder and louder. However, if this does happen I would not expect a prolonged European tour. Probably just hit the major markets but that is just my opinion. 

And...Claudio Trotta, an Italy promoter, posted this message on Facebook: "Maybe I've been working on a hypothetical tour for some time and both as a fan and as a touring manager, as much as I'm allowed in my role which requires some confidentiality, I like to share with you my work in progress...doing that seems to me a legitimate, nice and funny thing. Our man has announced an American tour and it seems obvious to imagine that he is considering whether to make one in Europe, it is equally obvious to think that his promoters in Europe are working on that and they hope to have confirmations as soon as possible...that's all." Sounds like things may be heating up for some sort of possible European shows.