I believe you should be able to convert the Excel date values to XML date values with this formula (in InfoPath)
xdDate:AddDays("1899-12-31", ValueFromExcel)
The value of xdDate:AddDays("1899-12-31", 42369) is 2016-01-01 (I believe the Excel value for 1/30/2014 is 41669).
If this is for display-only, you can have a Calculated Value control that shows this formula and that is formatted as a Date value, or you can use some Form Load rules in the form to do the conversion the first time a document is opened.