moving multisite to another domain

Reading so much I'm getting conflicted info. I"m currently hosting with godaddy on a shared server ( I use subdirectories for all my domains. I want to build a network using as the base. I have multiple other domains (mostly WP) with sites that will be added and realize I have to use Domain Mapping. The key is, I have to keep the existing sites active so can I build (copy) on, add the other sites and then transfer the network back to Is this possible or do I have to start over? Do I need to be a dedicated IP?