Personally, I think it should take place in a seperate timeframe from the main series. If it's just like the real manga, it'll be pretty gay; all the events would already be dictated, and there wouldn't really be any surprises. I think it should take place, like, in a seperate time; I mean, like, same worlds, same era, but no canon characters.
That way, it really is that whoever is strongest gets recognized as a captain or vice captain, and nobody has to be second to some NPC just cuz that's 'the way it is in the REAL Bleach!'
Why So Green And Lonely? We Are Accidents Waiting To Happen.