Well, I fully expect the Reds to be solid contenders again in 2012, so I don't see Walt & Co. going with someone unproven in the closers role. Sure, Chapman, Masset and even Homer have the stuff for it...but it's too soon for any of them with us in a competing role. They'll go out and get somebody fairly cheap to fill the void.
Now as to the individuals mentioned....yes, Chapman looks to be pen-bound again this season, but that is NOT their long-term vision for him. He's too talented to be relegated to less than 100 innings per season. I fully expect this season to be his last in the bullpen.
Masset certainly has the look & the stuff to be successful as a closer. But he's totally unproven up to this point. Now if he actually gets some considerable action in that role this season....maybe. But otherwise, he'll stay in the role he's in.
Homer is a bit of a wild card here in all this. He's certainly got the stuff for a closer, but he's also got the stamina and the stuff for a starter. If he fails to take another step forward this season, I think they'll try him in the bullpen next season. If he does step up, he's got the stuff to be a top of the rotation kind of pitcher. I firmly believe that this season is his make-or-break season in regards to his future as a starter or bullpenner. The lack of options simply solidifies this thinking for me.
Something not to be overlooked is the possibility of them re-signing Cordero to a much more modest contract for a shorter time-frame. If he does well this season and the team is successful, I could see it happening. I just can't envision Walt going with a young, unproven closer while in contention. I'm not saying I'd like this solution, just that I can easily see it happening.