This tutorial demonstrates how you can use BatchPatch to execute a script to modify local group membership on multiple computers:
Using BatchPatch to Modify Local Group Membership on Multiple Remote Computers
You can also use the same concept that is described in the tutorial above to create a local user account first. In the tutorial above we use the following command to add an account to the local administrators group:
net localgroup Administrators USERNAME /add
But you can use this command to first create a local account:
net user USERNAME PASSWORD /add