Hey kmagic! I have been wondering the same thing. So on a Mac I was able to:
1. open a PDF of some sheet music in Preview,
2. view 2 pages at once via the view menu drop down,
3. take a screen capture of the area I want, command + shirt +4, which saves it as a PNG,
4. open the PNG with Preview, export as a PDF, 1st clicking Advanced to change to landscape,
5. bring in to Bandhelper making sure you set Doc to Landscape
For more combine multiple pages into one file you would need a PDF software something like Acrobat. The resulting page (the way I did it) is kinda small even on an Ipad, I have attached a page for you to try out.
Lemme no what you think.
Cheers!