Looking at the space between the pickups and frets, I don't think its a 27.7" scale. It looks like it may be a 26" or 26.5". That would make more sense for C# standard. I could be wrong.
Not for nothing, but 1 1/2 full steps down really doesn't seem to need a special guitar. I mean, are you using 9's or something? Why not just use 10's or 11's, or maybe a proper setup and your guitar will stay in tune just fine. I really don't see the need for a longer scale instrument.
Just a shot in the dark, but I think for a player like Mark and based on what he was saying in the video, since he's a "shredder" and that type of playing typically requires a very light touch that heavier gauge strings even on a regular scale length tend to get cumbersome pretty quickly.
If you're primarily just a riffer/rhythm guitar player, it's probably not much of an issue to throw some 11's on a 25.5" guitar and have at it.
Just a guess tho.