If you're looking for ways to extend the rail system of your TM SCAR-L AEG, Echigoya has the right item for you... "Laylax Handguard Rail Extension fit for Tokyo Marui Next Generation Scar Series. This 163 mm can be extended using the hand guard rails allowing for more devices and accessories. Sling swivel can be also attached to the side."

This is mainly based on the Tango Down FN SCAR Extended Modular Rail System as described before and shown in this Gear Scout photo. Military Blog Japan has a better description of this product.