Create Flex Cable Extenders?

You can usually find the connectors for sale on various sites (eBay/AliExpress etc.) although they usually only sell the logic board side of the connector. An interesting thing that Apple does is to sometimes keep the same connectors from one generation phone to another, when the pin count doesn't need to change, but inverse the gender of the connector. This is because the pinouts have changed and it insures no damage is done by using the wrong version of parts.

Either way, you can also harvest the connectors. However, you will have to create a flex cable yourself and have it manufactured unless you can find someone who has already done this. There's also the requirement to get the flex cable out of the housing without it being pinched or causing issues with the tight fit between the screen and the housing.

Not impossible but it will require you develop your own flexible pcb with the proper software tools, such as KiCAD or EasyEDA. Have you seen this video where the guy essentially does this but for the Headphone port?