And if they DO pull it off, I totally called it.
You are not the first to make this suggestion, so no, you didn't "call" it.
As for your theories:
Reasons 1, 2, and 3 are based solely on cosmetic changes, wich if that is a reason for conspiricy, there are 1000's of conspiricies in everything.
The Sandman model, is a different model. Not just a reskin. Wich is the same for every other weapon for TF2's unlockables. Him holding it the same way as he did the other bat means they are just reusing animation. Wich they did for Natascha, Backburner, Axetinguisher, Ubersaw and so on.
In one of your "reasons" for it being a spy update, you claim Valve does a lot of these things because they like to be as lazy as possable. So why make a new can model for BONK! if they already have one at thier disposal?
Your biased against the Egypt map is obvious, it shouldn't even be used in an argument, so I won't bother taking too long to counter-point. I hate Turbine. A lot. (Yes I went there) Doens't mean they didn't add it. As for it fitting style, sure it isn't in Nevada Desert or the mountains, but it still has the freehanded stylized look of Team Fortress 2, so I welcome it. You forget, in the TF2 mythos, they have bases all over the world. (ironically usually 60 feet from each other)
Again, why make a new model for a can they have already.
You say they won't add new animations because they are lazy as possable. I suggest you start up TF2, go to the Commentary section, pick Well, and run around until you find the node that explains where your taunts came from.
Again, the baseball is purely cosmetic. Just because they are being lazy with thier display page doesn't mean its fake. Honestly, only those looking for flaws are going to freak out over a rotated/scaled picture of a baseball.
Since everyone can make achievment Icons, including Valve, why is that an argument? Did someone else make the page? No. It was Valve. Wich means if it were fake or not, Icons would have been made, making your point moot.
For reason 11. Read thier blog. 2 letters and a number for you, L 4 D.
You are right, it would be epic if it were really a spy update in disguise. And yes, Valve can be pretty lazy, yes, Egypt isnt the best map ever. But these are not support for a theory proving it. If they were going to make it a fake update, they would do everything they could to hide the fact, not foster clues. If they didn't someone (you in this case) would attempt to spill the secret, and soften the epic impact the update would have had on the community.
Sorry for pouring lava on your parade (rain is for wussies).
Finally a side note. If they were going to do an "Update is a Spy" thing, they will do it while using the engineer as the fall-guy. It fits too much in the TF2 mainstream for it to be anything else.