Partial Invoices

It would be nice to be able to send out partial invoices to customers in order to receive payment for part of the order in the case that part of the order has product that won't be in stock for longer periods of time without having to create a new job to fulfill at a later date.  Otherwise I think it would be good to be able to somehow link jobs together without having to use the notes section in the case that a job is split into multiple jobs in order to keep track of what was ordered by the customer more easily.  Thanks!