I don't think you trade Bailey. Volquez isn't healthy, Arroyo has a 5.5 ERA, Harang has been inconsisent, Owings is fifth starter. I just don't see enough pitching to trade off Bailey who finally has had success at AAA.
The obvious trade candidates are Alonso, Stubbs, Heisey, Cozart, Frazier, Wood. Frankly, I'd hold onto Wood more than the rest, pitching depth is key for any team. I'd also hold onto Cozart unless a better shortstop prospect comes back.
I think the Reds have to dangle some combination of Alonso, Stubbs, Heisey and Frazier to be players for a major hitter. Plus, maybe, one of their veteran pitchers.
I'm sure people would rather trade Francisco or maybe Soto or maybe others who haven't yet achieved at the high levels. I just don't think you get a major hitter in return unless the prospect has shown something at AAA or AA, or in the case of Alonso is a top rated guy.
Would Harang and Alonso plus lesser prospects bring back Matt Holiday? Reds would need an extension for Holliday or they can't do it, no rentals.