We are migrating 6 stores from nop1.5 to 3.1
Needed a way to move Customers as we do the migration.
nop1.5 provides a way to export customers  to XML, but nop 3.1 lacks a way to import customers
What I did was modify the Misc.WebServices Plugin - adding a method to read the XML and create a new customer.

Here is the class/code that does the work. I am sure it can be modified to work with other versions of nopCommerce.

http://public.justcloud.com/dua2mmemt2.64729035

enjoy