Allow customer to request a signature required on a shipment

[malice95]

I would like to add an option to the checkout process
where the customer could choose if they want to pay for a
signature required option for the shipper they choose. I dont use signature
required normally with fedex but I've come across a couple situations
where the customer would have liked the choice and would have paid for it.
(Lived in a bad neighborhood).

Ideally I should be able to set what the default is in the cart for the option.

[malice95]

It would also be nice if we had an option of forcing a signature required whether the
customer knows it or not (probably best hidden) to be added to the cost of shipping automatically if an order is over X dollar amount.

I am trying to keep shipping costs as low as possible for my customers while managing
risk.