Exactly, a higher level than Bankai wouldn't even make sense for all the reasons you mentioned, plus the fact that Bankai means Final Release. After thinking it over again though, I wouldn't really be surprised if Kubo introduces something like that eventually. If he continues the story for much longer, he'll eventually need to find a way to power up shinigami powers and give the fans something new. Hollows can evolve and become stronger as long as they devour other Hollows, and if this is indeed how Hichigo grew stronger, then it means he'll keep getting even stronger. However, he can't be stronger than Zangetsu, there must be a balance between the Hollow and Shinigami sides. And at this point, I don't see much room for improvement for Zangetsu, except from through time and experience... And not just Ichigo, the captains and other important shinigami will also need a power up if they are to keep having an active role in the plot. So I'd say it depends on how long the manga keeps going...

Logic says no, but the fanboy in me says HELL YES! lol
And I think Kubo doesn't really pay attention to such boring and insignificant things as 'logic' lately, so who knows... XD

I don't think there is. Once Ichigo reached Bankai to level up he had to gain hollow powers and now use the bankai's final move. Neither is surpassing Bankai, just adding power to it.

No, what I meant was that Ichigo did not reach a level above Bankai, just increased his power by gaining the hollow powers and the final technique. Neither evolved the Bankai just added strength to the Bankai's strengt by raising Ichigo's

Well just cause they can go bankai, doesn't mean they are at full power. This is because someone like Hitsugaya hasn't mastered his Bankai, yet he still is on par with many strong warriors. Ichigo could possibly continue to develop his powers as he masters them. His bankai still seems small, compared to other bankais which normally have a big effect. Some may argue the Final Getsuga was the "Big" part of his bankai which is reasonable.

Im not sure yet, still very vague. His fullbring WEAPON, not the clothing, reminds me of his Full Getusga with his dark reietsu looking thing. All it's been common, since his bankai's activation, that apparently his clothes represents how much his has left in the tank. SO I wonder indeed.

I agree, it looks like a bankai, but also notice that his fullbring sword is fused with his arm just like his transcendental state. I don't think it;s a coencidence.

  Yes I'm not crazy. So far it looks like a rietsu base weapon, since that's how it looks like for Getsuga Tenshou and Final Getsuga. Also didn't they state he was finally at Post-Bankai or something?