I personally don't think so. I mean, Himaruya might make some comical hints at it but I don't think there will be any major ones announced official. But if he were to, there would need to be something historical backing it up, or else it just wouldn't make sense for it to be in Hetalia.

It's not only that,but he doesn't want to cause chaos for people who support other pairings. Like FrUk and USUK. If they both became cannon, then...bloodshed, it wouldn't be safe to do anything anymore cause fans from both pairings will hurt each other. Also the letters Himurya would get. I think historical has nothing to do will all of it though.

^True. The fans do get pretty crazy when it comes to their OTP.

I don't think Himaruya will make FrUk or UsUk canon, he doesn't want to tick anyone off. GerIta is pretty much canon anyway, so Himaruya letting it out won't change much.

PruHun looks like it could be made canon, as does Spamano.

.......but then agin i have no idea

@pumpkinqueen: Yeah. Most people back up GerIta because of the theory of HRE is the child version of Germany, which may or may not be true and HREXChibitalia is pretty much cannon.

Actually, I heard it's getting more canon. There was a scene in the manga were it was either little Germany or older HRE and they looked just alike.

^Well historically speaking they would be the same person. Because a large part of the Holy Roman Empire was made up of Germany. And when the Holy Roman Empire fell, Germany rose.
But I don't know if it would really mean anything for Gerita. I mean, even if Himaruya announces it himself, Germany still would have thought Italy was a girl when they were kids. And there's not really that much historically wise backing up Gerita except that they were allies during World War II and the Pact of Steel. But even in World War II Italy left the Axis Powers for the Allies during the end of the war.

I don't see FrUk or UsUk becoming canon in any way.
GerIta, is about the only one I see becoming canon, to be honest. If it does happen.

Hetalia is a seinen manga and the characters' relationships with each other are reflecting the real countries' political relationships.
Based on these two things, the odds of a yaoi pairing becoming canon is 0%. Or in best case, 0.1%.