I don't know if you could exactly call it a MD file, but what I've been running recently has been:
It got me a nice streak until I lost to Fierte Pixies earlier today.
The open is Defect-Shade-Astasria, or against Lawtia's T2 undead, Defect-Shade-Withdrawal. The T3 set has the bonus of getting rid of Defect; Sadgasm's TGC file (which is what the open of this file is based on) uses Sin SS, but I find that too ineffective, especially when your opponent expects it.
After that, Plant Mage usually follows with Astasria as a 70 HP tank to gen SP. Depending on the situation, either Ermitage or Sulana is set T5; Sulana if I expect a lot of grims or the enemy is being extremely aggressive and picking off too many copies of Astasria, and Ermitage otherwise.
The idea is to stay on the defensive for the majority of the early game, attacking only when necessary, returning dangerous units, and setting Church Paladin after enemy unit closes to off-tank and guard against damage SS.
Once I've generated enough SP, or once the opponent has a developed field, I set Catira against bigs or MD Cannon against mids/rushes. Catira takes care of Star Dragon, spaceship, and other high HP units in general like Shin, Bringer, etc. MD Cannon has a 2 SP full field wipe skill and can also tank from the front row with 70 HP (90 with Sumer) and can get upwards of 30 + 20 (Sumer) + 90 (Astasria) = 140 AT, though usually it stays around the 50-70 range. The problem is her AGI; I've usually just had Ermitage buff her for AGI and rely on Sumer's +1 AGI too, but when Ermitage isn't on the field and 2 AGI isn't enough it does become a problem (which I've recently learned in that Fierte Pixies match). Teching a Sylph or something might be a good idea.
It has a lot of weaknesses, though. You have to jump through some hoops against T2 Tidal on your Defect in order to get that first SS off. Against Serpent files that especially becomes a problem when they set Frog to engage your Defect (which you can remedy with a Shade Withdrawal; 2 Falkow isn't hard to get to). And Fierte is definitely a problem. The file also has a hard time gathering momentum against files that rush out aggressive mid-level units early in the game (Urgrant, Belus, Jack is also a hassle because he bypasses Church Paladin's open). It's a gimmick file, as most Gald SS files are.
I really don't get why more people don't use MD Cannon, though. She can tank, and she can wipe the field for 2 SP. Astasria's auto synergizes really well with her.
As a side note, Sulana is so good. 2 grims in one turn for 1 SP? That's like that one level 2 falkow unit what's her name. Except you also get back one of your dead MDs, and you also buff and heal an MD. And if you don't want to spend 1 SP, you're still grimbaning as a 0 SP auto skill. The only other card that has a 0 SP grimbane auto skill is Fellana, but she also self-grimbanes. A traditional MD file might have file space issues, though, and might have a hard time finding a turn to set her without interrupting the rushtime tempo that MD files are focused around.