Cap on orders through web store

We would like to place a cap on orders placed through our web store. We have had problems with fraud, customs delays, and customers choosing improper shipping that cause significant losses for larger orders. Unfortunately, there doesn't seem to be anything like that built into NetSuite.

The workaround I came up with is to set limits on -all- of our public shipping methods so orders over a certain amount have no way of shipping, thus cannot be completed. This is a less than ideal workaround for us, because some of our custom shipping methods (First Class International, for example) need to be limited by weight and shipping items cannot currently be limited by both weight and order amount. I basically set a value of $9999 in the shipping table for orders over the weigh limit, but that may confuse customers. It also doesn't let us set