Just make sure the FFL side is NOT inverted flare. (Common for propane fittings)
That fitting will not mate well with the standard male flare on kegs and
you won't get it threaded.
Here is one:
http://www.chicompany.net/index.php?main_page=product_info&cPath=375_19_220_284&products_id=1555...
I have a similar issue connecting a ball lock connector with MFL to a pressure guage.
Not sure if you are willing to use two parts, but I have been looking for the same adapter. The only solution I
have found is a 1/4" FFL to 1/4" MFT (Amazon). Then you can connect a 1/4" FPT-FPT coupler...