I think you could make in admin menu - Registration Field Groups similar to Field Groups.
Maybe would use it many of users.
For example in need it for:
Basic company detail:
- company name
- Reg. ID
- VAT Reg ID
........
.........
Billing Address
.......
......
......
Postal Address
........
.......
.......
Contact details:
- Main phone no:
- Additional phone no:
- Email address
For the Future ;-)
Each one group would have a Checkbox - copy to invoice
Auto copy field groups to invoice created for user.
For Example:
- Basic Company Details
- Billing Address