Add/Edit Item form with Repeater-like field

I need to have a complex Add/Edit list item form which contains a property that contains arbitrary number od rows.

For example: "Order" Content type with "OrderLines" field. A user must be able to add/remove rows when creating or editing an item.

What is the best way to implement this?

Ideally I am looking for an OOTB solution (no matter free or commercial), 'cause I'd like to avoid creating a custom field myself.

It should also allow to define the structure for a row item (for example Order Line with Lookup to the Wares list and Quantity field) and (ideally) to define a lookup to an BCS list with an external content type.

Any help is appreciated.