I'd like to be able to import a spreadsheet from Excel into SharePoint and be able to select a list template I've already built. Is this possible? I need to be able to do this so the proper workflows are attached automatically to the list. I'll need to create a new list because I'll be getting a different spreadsheet for every order.
Associate your workflow with a content type.
Extend Mike's suggestion by creating a new list instance which will already have the content type associated with it. As your workflow is associated to the content type you will have the workflow available in the list.
I'm assuming you're looking for a reusable method that's got some automation.
I'd imagine you could use an Excel macro to call the lists web service, prompt the user to select a template, create that list, then push the data into the list.
You may need to store the list structure CAML in the macro vs. in a template file, as I'm not positive if lists created from a template will inherit workflow (I've never tried that).
Create your list using your template and make sure the columns match the excel doc. Then open the list in the datasheet view and copy and paste the cells from excel into the datasheet view.