Is there a 30-pin LVDS cable extension for Macbook Pro display panel?
IMHO I think it will be hard to make it work without disassembling the whole screen. The main reason for this is that the pinout of the connector coming out from the screen you attached in pic (whether 30 or 40 pins) is customised by Apple and may not correspond to the 30 (or 40) pins pinout of the connector soldered on the screen. For example, on some model I have seen that the producer puts display, camera and mic all together.
Even thought you will be able to find an hypothetical female-female adapter, then, it is not 100% sure that will be pin correspondence. 

One think you could do, if you want to proceed in finding an 1-1 adapter, is finding the schematics of the Apple LVSD cable that comes out of the screen and check for pin compatibility.If positive, then look for a female-female adapter.

Or, in case you have money to spend into a new adapter (or build one yourself) have a look here&lt;: http://dp2mbpr.rozsnyo.com/ or here https://hackaday.com/2013/07/05/macbook-pro-retina-display-with-a-normal-computer/

Ciao!