In Ubercart, users could modify all aspects of line items including the product title (i.e. the line item label). In commerce, this ability was removed and the title for product line items is always equal to the referenced product's title.
This module adds a new line item type that allows for manual entry of all line item properties, namely the SKU, title and unit price. It does not associate itself with products and manually entered line items are not re-usable (for now).