I am looking to build a SAAS website builder similar

Hi

I am looking to build a SAAS website builder similar to edublog concept.

I am also a domain reseller with enom and a hosting reseller with site 5.

1. How do i create a system like edublog http://edublogs.org/why-edublogs/ where they bundle the hosting packages and diskspace with personal email all in 1 system? How is it all integrated?

How do i automatically do space allocation, domain and email setup?

Thank you