draft sale order launch draft purchase sale order

Imagine your customer asks some product prices to you. You register a draft sales order. But you have to ask for prices to several suppliers to select the best one and the biggest margin for you before confirming the sales order to your customer.
It would be very useful to have a button for creating draft purchase orders from draft sale order.
Then... where you receive all products prices from all suppliers, you can confirm the best and cancel the others.
It would be also helpful to have the posibility of updating all suppliers prices on products form from the draft purchase order. Even if this time you don't choose them, maybe you will need to have the information useful next time and you don't need asking same information to suppliers again.
Once you choose the best supplier conditions you can offer your best price to your customer...Then he can accept or not the proposal...
This is a real case...