Multiple ship from Locations

I am looking for someone to work with me on customizing product cart to do the following:

1. Add an option for  Add / Edit vendor under the Store Management Tools menu.
2. Add a drop down in the product add / edit pages to select a preferred vendor.
3. Add a check box in the product add / edit page to indicate drop shop from preferred vendor (checked)  or store address (unchecked).
4. Do the associated code to calculate shipping charges.

Real simple stuff!  Should only take an hour our so right? Just kidding.  I know that this is a tall order but I would really to to discuss it with someone.  I know that the guys are thinking of puting similar features in a future version but I don't know if I can wait.

Thanks

Since we are indeed working on new features that will address this area of the system, we felt it was important to participate in this conversation. ProductCart v3, which will likely be a Q2 release in 2006, will include a comprehensive Vendor Management system that will allow you to perform a variety of tasks that are related to managing a store where products are purchased from different vendors and sometimes drop-shipped by them.

However, there is one aspect of this new feature that we would like to ask an opinion on. Specifically: assume a customers orders 3 products, supplied by 3 different vendors, and that all of them are drop shippped from the vendors. How do you envision shipping costs being calculated?

1. As the sum of the three different shipments (this does NOT appear to be the way large ecommerce stores determine the total shipping cost for the order as it might lead to high shipping charges and turn off customers).
2. As the simple average of the three shipments. E.g. (4.95+5.55+7.65)/3
3. As the simple average of the three shipments, plus a correction. E.g. an extra 10%, like this: ((4.95+5.55+7.65)/3)*1.1
4. As a weighted average of the three shipments (if so, how should they be weighted).

This is a very important - and complex - "piece of the equation". A study of major ecommerce stores (e.g. Amazon, Buy.com, etc.) does not seem to point in any particular direction. As mentioned above, however, it does seem like they do not charge for every shipment that occurs to fullfil the order (this is also true in a case where one or more of the products are shipped separately because of a back-order).

Your feedback is very much appreciated :-)