Support for Support Plans/Service Level Agreements

Has anyone implemented Support & Services to track customers against specific support plans? For example, we have two support plans: one that is 24 x7 and another that is 12 x 5. We need to manage customers against these plans when cases are submitted (particularly at night and on weekends).

We also need to annually re-up these agreements so need scheduled recurring billing implemented to notify us of when a new agreement is due and invoice the customer.

Finally, we need to apply the plan as a percentage of product sold (NetSuite does not support percentage-based services, only markups which go away once the sales order is processed). In addition to being able to add a line item for the support plan on a quote which will multiply it's percentage value against the products being sold in the quote, we also need to be able to prorate additional quotes to the annual cycle so we are not causing multiple renewal dates for the same customer.