Request Form: submit multiple requests at once

Allow the request form to create multiple tasks with different custom fields. 

Use case is for purchase requests. We'd like to have a user submit a request that creates a task (or project) to place the order and subitems for each of the lines of the items to be purchased. The request form would need a table, like below, to collect the separate custom field values for each of the items to be purchased, and allow the user to add lines as needed. The math for each line item's cost could already be calculated in a custom field. The custom field could have its default aggregation be a sum.