Apologies about being late to the party for images on this one, but I have one to contribute myself. Megatron Megabolt's color scheme definitely goes best with Brave Max. I've never even tried with original Fort Max. The "Dark Maximus" combo has been so-named and physical connections were made by others as soon as the toy came out. I did a couple of other additions with my Dark Maximus, but the full-body shot expresses how good the combo normally goes.
Yeah that does look bad ass! I don't have a Fort Max or Brave Max though. All I gots is a lousy green Megabolt head! I moved him out of my Megs set up and replaced him with Universe Galvatron anyway. I need to find a cool place to put Megabolt. I wonder if I can fit him on my 18 inch Talking Ash figure from Army of Darkness?
Oh man... it would've been so cool if they actually had Megatron turn into a headmaster for Fortress Maximus on the show. Y'know, if the show lasted longer, and they made an episode where they found the original Fort. Max. =D