Is there a script available to make an alternate size layout of a book?

Hello:

I was referred to this forum from this thread: How can I export a pdf of an InDesign alternate layout from a book?

I have a book that is in a 6×9″ layout and I would like to make an alternate layout of the same content for 8.5×11 (and other formats).  I found out that I cannot create an alternate layout in a book and export just the layout, without including both sizes; I have to create a whole new set of book files.  Is there a script that can do this or at least do some of the heavy lifting?  It will need to take the current 6x9" format and make it 8.5x11" and also adjust the text frames for the larger size pages.

Thanks for any help!
Kevin