InfoPath Dev

I am converting some of the forms on our Intranet (moving from printing word docs and sending internal post) to electronic InfoPath forms.

One area that keeps coming up and challenging me is when a form needs to be completed by more than one person/department.
For example FormA needs to be filled out by an employee, they then need to submit this and have it routed (maybe email maybe sharepoint workflow) to their manager for further comment and approval.
Both parties would sign (which I have sorted). The document would then be stored in a separate folder (not necassarily the SP forms library) so other couldn't read the contents.

I guess I'm asking how others have achieved this in the past to save me rethinking the wheel.
Infopath 2010, sharepoint 2010. Could be either a browser based or filler form.
Always internal people (same domain).

I may have brainstormed myself an answer
Promote a couple of columns out to sharepoint (don't need to be shown in the view) and piopulate this with the managers name and the stage the form lifespan is up to.
EmployeeComplete = True/false
ManagerComplete = True/False
EmployeeNotified = True/False and build a workflow on that