Looking for the same thing -- well, similar. First and foremost, there will be no online purchasing; it's all on-site (I already figured that part out).

I'd like the ability for non-registered users to be able to create an estimate (or quote) and then the staff can contact the user with a total.

Users who register will have to be approved by staff in order to make a "purchase order"; they can see the pricing and all they need to do is submit an order.

Any ideas?