Hello Tim,
It would be a very involved process. I had the Estimate to Sales Orders actions in mind. If you look at the QuickBooks_Estimate screen and the Create Sales Order actions in the More Actions... menu, you will see the actions. The most important is Insert Records Into Table.
The Sales Order to Invoice is more complicated because you are choosing individual line item records, not fields. The screen is QuickBooks_SalesOrder_CreateInvoice. There are many actions here and I don't know much about them.
If you are looking to do this, I would talk to one of our Method Solution Providers or Method Partners. They may have a better way of building a system and workflow that meets your needs. This is a complex customization.
Greg