This is a bother, I know, but one way to "start fresh" is to do this (I'm not suggesting that everybody do this, but if you know what you're doing and don't mind "starting over", this method worked for me):
1) Go to your folder on your local machine: ~/library/MobileDevice/Provisioning Profiles (you may need to use the "Menu > Go > Go to Folder…" command to access "~/library" since Apple doesn't make that folder easily accessible since perhaps OSX 10.7).
2) Optionally trash all profiles within… this is a somewhat severe move, so again, I'm only suggesting this as an option for those who want to "start over". That being said, removing these doesn't actually "nuke" them forever, since you can re-download and re-generate them from the Apple Dev Center.
3) Log into the Apple Dev Center and access the "Provisioning Profiles" section. Delete the ones that you don't want anymore, or just delete all of them and re-create new ones for the provisioning types/permissions you need. Which step you take is entirely up to you, and I will not be held responsible if you remove things in here that you shouldn't.
4) If you removed all of the profiles in Step #2, you'll need to re-download the ones you want to use again. This can be done by clicking a profile (from the list in the Apple Dev Center list), clicking "Download", and the double-clicking on the file that is downloaded (presumably to your Desktop, but could be elsewhere depending on your browser settings).
5) Back in the "MobileDevice > Provisioning Profile" folder in the Finder, you should see new files generated for those that you re-generate.
6) In Xcode, go to: Preferences. Click on the "Accounts" button on the top bar. Select your Apple user account, and look for a button in the lower-right called "View Details". This should bring up a sub-menu. At the lower-left of that menu, there should be a little "refresh" button that looks like a recycle arrow. Click this, and Xcode should refresh the list of provisioning profiles.
7) Now, quit the Corona Simulator and restart it. Under the "Build" menu, your list of profiles to select should match the list that you just cleaned up.
That's it! I realize that they're still not in any specific order (something we could improve on), but at least the list doesn't have age-old profiles in there which are dead, dysfunctional, or whatever.
Again, use this method at your own risk, and only if you know what you're doing. I can't be held responsible if you mess up your provisioning profiles thing in Apple's system.