My iMac has two non-matching displays. When I connect from my iPad using iTeleport, only one of the displays is visible. Is there some way to configure Screen Sharing so that both displays will be available?
This is probably not a problem with Screen Sharing, but a problem with iTeleport. Using screen sharing's default setup, I can see both of my iMac's displays from another computer:
And, it appears that iTeleport also supports multiple displays (see their FAQs).
I suggest that you check the connections to the extra display, and see if there are any settings for iTeleport.
You can also look at the Screen Sharing preferences by opening
/System/Library/CoreServices/Screen Sharing.app and going to Screen Sharing-> Preferences. However, it doesn't appear that that allows you to change which display(s) are used.