Migrate subdomain-based multisite to WPMU DEV Hosting

We have two multi-site we are going to want to move over and they are both subdomain installs... one of which has a handful of sites, but the other has over 100 so I'm wondering what we should try to make this happen.
We are really excited about moving to your platform and we have a WordPress developer and are also willing to work an agreement with you to find a way to make this happen.

I tried using Shipper, but I get this error on Pre-flight Check: "Your destination server configuration is complte, but you have an error which prevents the migration". I was confirmed on chat that this is expected behavior of Shipper since subdomain to subfolder migration won't work.

We would really appreciate if you could help us with the migration, thanks.