The other angle of this is how do the Colts maneuver to get what they want and still keep the rest of the league guessing in order to keep the value of the #1 pick. If the decision on Manning is made before the draft (which that March 8th bonus would seem to dictate) then they could lose a lot of leverage with the #1 pick. If Manning is not paid indicating he'll be gone then it's pretty obvious the Colts will stay put and take Luck or MGIII. This route puts their cards on the table and they'd have to stay put and take one of the QBs. The rest of the league would really have to pay up to get that #1 pick, which would be good for IND but they'd have to stay put and use the pick on a QB.
If Manning stays on the roster, come draft time then the Colts have left the league wondering. That would give them leverage with the pick to possibly deal it. But if they want to rebuild I don't see how they can pass on Luck and if so then they can't pay/keep Manning. They just need to put their cards on the table, like I said, not mess around and just do what they have to do.