I have seen MALLC. Execution is EZAF. I tried it with my Sheik controller setup and it's easy to do. It doesn't even have a crapton of application either because Nair and Fair have too short of a landing lag to benefit from such a tech.
His remaining aerials: dair, bair, and u-air, all have problems making them usable with this tech. Dair is virtually useless because it only works on landing, u-air can probs be used for juggles, but only extending it one move as you would have to remove your monado art to do the tech again, and bair, although definately the most viably used, doesn't (imo) have as good frame data as nair or fair. Bair is still debatable tho. I don't main shulk so I can't claim to know how effective the one is. Still, one major issue arises. You have to reset manado to neutral to continually use this tech.This is extremely dumb and quite frankly promotes less usage of this tech.
I have also seen MADC as well. Although it has more application, it's still kinda eh due to the problem stated above. And then you realize that sheik virtually has these EXACT same techs but work better because she doesn't have to reset to neutral madado. In many ways it's even better other than that. The tech's I am referring to are sheik's instant needle cancels. You can argue that instant needle cancels don't actually continue combos, but that's of almost no consequence because Sheik doesn't NEED help making combos longer. Fair strings and f-tilt locking work just fine on their own (with a plethora of other comboing tools that I don't really need to go into). INCs start these combos that rack up a clean 30% each. INCs are also faster than MADC and MALLC too, aswell as the fact that INCs can be used as movement tech aswell. Add in the fact that you can C-bounce into INC and it becomes an even better tech than MADC and MALLC could ever be.