To add my comments to the mix...I created my store in 10/2009 using one drop shipper. I later found another drop shipper offering as many products in quality and price as my initial drop shipper did. However, here is where the problem arises for me.

My initial (first) drop shipper charges shipping by total COST of the order, not by weight. The second drop shipper I wanted to add to my supplier list charges shipping (conventionally) by WEIGHT, not by cost. So an obvious problem in trying to use them both.

Also, as it has been mentioned earlier in this thread 1) how would shipping be calculated at order checkout using two totally different methods of determining shipping and 2) if a customer orders products from drop shipper A (shipping calculated by cost) and also from drop shipper B (shipping calculated by weight) how could/would that be intergrated into the checkout process?

For me I've had no choice at this point but to choose one or the other as a drop shipper but not both. The issue I would have trying to use both of these drop shippers is calculating the shipping.

There are many great points made in this thread. While creating such a mod would be a major undertaking it wouldn't be impossible with input from many who were interested.