Pro Sites + Domain Mapping = Free Domain with Top Level Signup

The next step for Pro Sites would be to include a way for a specific Pro Site level to qualify for a free domain registration (through Enom) via the Domain Mapping and Pro Sites plugins. Of course, this would have to happen after the trial period and probably a yearly fee is paid.

WHMCS already does this but i don't really want to go that route since Pro Sites works much better with WordPress.

Maybe this has come up already but i could not find a Q&A or forum post regarding this subject.

Anyone have another idea to make this happen automagically?