Orbeon offers an Excel import to be used together with their Form Builder (described here).
Is it possible to integrate this import into their XForms engine?
This import function is designed to work specifically with Form Runner. It cannot be used directly with plain XForms because it follows Form Runner assumptions about the data format, XForms instances, etc.
It could be modified to work with non-Form Runner forms, but that would be some work and you will have to understand XForms and XSLT. You can see the implementation here.