I know a childminder who tried to open a 'like childminding' setting but Ofsted refused to register it that way, it had to be Childcare Non Domestic (wording Ofsted uses on their 2012 inspection report), so a nursery.
They changed due to:
Their own children were getting older and did not want little children in their home.
Their home was becoming more and more like a nursery, they wanted their lounge back for the adults and a room for the soon to be teenagers.
They were running out of space, they were at maximum capacity and still had new enquiries every month.
They now do before and after school care, do all day creche/nursery and have recently been approved for deliverying funded education (no the approval for that does not automatically come when you change registration type, as it is LA decision) so have a separate pre-school. They run from a building with two large rooms, one is the before/after school club and is pre-school, the other room is the creche/nursery.
They have children on contract as well as ad-hoc PAYG, the PAYG service has proved popular and it is useful for days when the nursery is low on children - as staff are paid regardless of how busy they are.
Quite costly to setup, takes a while for the registration during which time there are building related costs, including business rates. Getting a good deal from the landlord is cruical to avoid too much paying for time when you are not having any children.
Financially setup as a limited company, so you can order their accounts like you can for many nurseries.
The ex-childminder is now, some 18 months later, starting to get more free time. Whilst being manager/owner, they have a good team of staff so do not need to do quite so much handson management. Keep in mind that if making this change, you are no longer in the adult:child ratio as the manager.