Seeing as I am speeding through Hyouka I figure I'd make some deductions. Taking this and what previous statements we have to assume the following.
1) Bleach isn't budging from it's time slot anytime soon.
2) Thundercats is going to repeat
3) One Piece IS airing this year meaning they are planning to make it the replacement for GXP, Symbionic Titan,
Eureka 7 or will eat up an episode of Cowboy Bebop and/or Inyuasha. Any other show would have to be canceled (please god Bleach) in order to fit that timeline.
4) We still want a rotation of new and old shows to keep things fresh
Assuming all these things I would guess One Piece would take Naruto's slow and the schedule would be as follows.
12:00 - Bleach
12:30 - One Piece
1:00 - Naruto
1:30 - Soul Eater
2:00 - ???
2:30 - Eureka 7
3:00 - ???
3:30 - Fullmetal Alchemist: Brotherhood
4:00 - ???/Cowboy Bebop
4:30 - ???/Cowboy Bebop
5:00 - Inuyasha
5:30 - Inuyasha
With Thundercats being reshuffled who knows will it will end up and I assume they will hang on to SBT at a later slot since they really have no options for western animation. There is also Ghost in the Shell to keep things fresh.
Technically you can expand One Piece to an hour but that just extends the Shounen hour and it really hurts Soul Eater and Naruto which both pull great numbers.
In conclusion it is a bitch to schedule One Piece in the block period let alone make it an hour. It is way too big a franchise to stick in at 3 like GXP and we don't know if it can overcome its stigma and be poorly received. If handled well with great promos I think it will run fine at 12:30, one episode a week (keep in mind only 240 episodes are dubbed) until the schedule opens up. Then we can look at 2 episodes a day up to when we catch up to G8. The important thing is getting One Piece started because the series is constantly growing and every week it isn't airing just makes the task of airing it all the more daunting.