Customer Inputed Shipping Cost?

Is there any module out there (or any way) that the Customer can MANUALLY type in a Shipping cost which will be added to the Order?

The reason I ask this, is that the cart im creating has items where shipping cost cannot be worked out on just dimensions or weight or per unit or anything like that. These products are large cranes, and shipping costs vary's on every order. So i would like to have customers CALL FOR FREIGHT COST, and then they can still use the Cart by manually entering in the amount quoted.

I know it leaves option for some people to abuse the system and possibly create void orders, but it's something that I can live with and would love!!

Any idea's ???

Thanks
Ross.

Anyone??????

To the best of my knowledge, there's nothing available for this particular purpose right now.

The way I would approach this would be to modify the coupon system and have them enter a code or value that would be added to the cart total. Alternately, start with the low order fee module and algorithmically determine what the shipping would be based on the cart contents, delivery address, etc.

Good luck,
Scott