We have found a company that has a $199 module that accepts .csv files exported from x-cart and imports them to QuickBooks Online Edition. We ran a trial, and it looks like it will work. We are planning on doing the export/import once a week to keep our e-store and physical orders together in QBOE.
Here is the company.
Transaction Pro Importer
http://www.BaystateConsulting.com
Let me know if anyone sees a potential problem we should be thinking about.
FB