As it stands right now, the Royals rotation is:

1. Meche
   
2. Bannister
   
3. Greinke
   
4. ?????
   
5. ?????

The question marks would be filled by two of Hochevar, Hudson, Bale, De La Rosa, Davies, Nunez, or Wright.  That wouldn't be too bad, but you can't think of a rotation as going five deep.  The reality is that because of injury or poor performance, every major league team is going have to give some starts to other pitchers over the course of a season.  Last season, major league teams gave an average of 31.6 starts to pitchers outside of their top 5.  That's amounts to basically a full season of starting pitching from your #6 starter pool.

So the likely rotation would actually be:

1. Meche
   
2. Bannister
   
3. Greinke
   
4. ?????
   
5. ?????
   
6. ?????

Most of the team's starts would come from a pool of talented but iffy pitchers who may or may not be ready to be major league starters.

If, however, the Royals signed somebody like Lieber, Benson, Jennings or Clement, the rotation gets much more solid:

1. Meche
   
2. Bannister
   
3. Greinke
   
4. Lieber/Benson/Jennings/Clement
   
5. ?????
   
6. ?????

One could argue that since 2008 is still a rebuilding year, we should have as many rotation spots as possible open for extended tryouts/auditions and to give these young pitchers major league starting experience.  The first problem with that is that 2008 isn't a pure rebuilding year.  We're not at the bottom of the rebuilding curve; we're well on our way up and not too far from contention.  I think this is about a .500 team.  We have to balance player development with getting more wins.  In addition to rebuilding the team, we're rebuilding the fan base and, perhaps, a "culture of winning."  I'm ok with using a couple of spots in the lineup for extended tryouts (SS and 1B), but not more than half of the team's starting pitching.

The second problem with the maximize tryouts philosophy is that the most talented pitchers on that list (Hochevar, Nunez, Davies) would probably benefit from extended time in the Omaha rotation, rather than being forced into the major league rotation because the rotation is too thin.

So my rotation would probably be:

1. Meche
   
2. Bannister
   
3. Greinke
   
4. Lieber/Benson/Jennings/Clement
   
5. Hudson/De La Rosa/Bale

That is a fairly deep rotation.  If one of the top four falters or goes on the DL one of the two #5 SP candidates who didn't make it can step in.  Hochevar, Nunez and Davies should be anchoring the AAA rotation.