SkyFire - first, that's really amazingly awesome. Thank you.
But...but... where the heck would you go from *there*?
You have to have this scene before you introduce the bleach crossover, or it loses a lot of its cool factor. You can't do a whole lot after this scene, because honestly, once Emiya can spam Bankai, there's not a whole lot that can stand against him from either series. You can't just run this as the last scene to a longer piece that doesn't include Bleach, because then it's just an ugly Deus Ex Machina, rather than an awesome crossover seed (unless you larded in the foreshadowing... and that's basically impossible to get the balance right on).
still... maybe one to four chapter's worth of prologue, showing the Grail War as it falls to suck (possibly due to some shadowy dealings by people who are later revealed to be Bleach villains), and then a time jump forward to this scene (not dwelling too deeply ont he suck int he middle, because it would do bad things to the feel of the piece) followed by a jump back to Shirou's adventures in the world of the dead? That *might* work, but it would still be tricky in bits, particularly towards the end, where you try to fit this scene back into the plot.
But...but... where the heck would you go from *there*?
You have to have this scene before you introduce the bleach crossover, or it loses a lot of its cool factor. You can't do a whole lot after this scene, because honestly, once Emiya can spam Bankai, there's not a whole lot that can stand against him from either series. You can't just run this as the last scene to a longer piece that doesn't include Bleach, because then it's just an ugly Deus Ex Machina, rather than an awesome crossover seed (unless you larded in the foreshadowing... and that's basically impossible to get the balance right on).
still... maybe one to four chapter's worth of prologue, showing the Grail War as it falls to suck (possibly due to some shadowy dealings by people who are later revealed to be Bleach villains), and then a time jump forward to this scene (not dwelling too deeply ont he suck int he middle, because it would do bad things to the feel of the piece) followed by a jump back to Shirou's adventures in the world of the dead? That *might* work, but it would still be tricky in bits, particularly towards the end, where you try to fit this scene back into the plot.