ringtone tab missing in itunes device

Not sure if this will solve any of your problems, but here's how I got my Ringtones to sync to my:

iPhone 4S,

MacBook Pro,

iTunes 10.5:

1. Your music files have a specific format that allows iTunes to read them (usually .MP3)
2. Your Ringtones also have to have a specific format in order for iTunes to know what to do with them (.M4R)
3. Some of your ringtones might be in .MP3 format (or you might have clipped out a certain part of a song you like from an .MP3 file). In order for iTunes to recognize your Ringtone as a Ringtone file, it HAS to be in .M4R format. I don't know if you can just change the file type manually (i.e.: type in .M4R where .MP3 is). If so, then you can use a batch renamer program like "A Better Finder Rename" for Mac, or some other utility)).
4. If just manually retyping the format doesn't work, then I would use a program such as WonderShare's "Video Converter Pro" which will let you convert Audio and Video files to other formats.
5. As soon as I started the Video Converter Pro batch conversion from .MP3 to .M4R, Video Converter Pro started importing the new .M4R files into iTunes (10.5) and magically the "Ringtones" tab appeared on the left side of the iTunes window, as well as along the top with the other iTunes tabs such as Summary, Info, etc.

After that, just go to the Ringtones tab at the top and click whichever Sync button you like ("All" or "Selected Ringtones").

Hope this helps,

J.